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  • Maven does not resolve a local Grails plug-in

    - by Drew
    My goal is to take a Grails web application and build it into a Web ARchive (WAR file) using Maven, and the key is that it must populate the "plugins" folder without live access to the internet. An "out of the box" Grails webapp will already have the plugins folder populated with JAR files, but the maven build script should take care of populating it, just like it does for any traditional WAR projects (such as WEB-INF/lib/ if it's empty) This is an error when executing mvn grails:run-app with Grails 1.1 using Maven 2.0.10 and org.grails:grails-maven-plugin:1.0. (This "hibernate-1.1" plugin is needed to do GORM.) [INFO] [grails:run-app] Running pre-compiled script Environment set to development Plugin [hibernate-1.1] not installed, resolving.. Reading remote plugin list ... Error reading remote plugin list [svn.codehaus.org], building locally... Unable to list plugins, please check you have a valid internet connection: svn.codehaus.org Reading remote plugin list ... Error reading remote plugin list [plugins.grails.org], building locally... Unable to list plugins, please check you have a valid internet connection: plugins.grails.org Plugin 'hibernate' was not found in repository. If it is not stored in a configured repository you will need to install it manually. Type 'grails list-plugins' to find out what plugins are available. The build machine does not have access to the internet and must use an internal/enterprise repository, so this error is just saying that maven can't find the required artifact anywhere. That dependency is already included with the stock Grails software that's installed locally, so I just need to figure out how to get my POM file to unpackage that ZIP file into my webapp's "plugins" folder. I've tried installing the plugin manually to my local repository and making it an explicit dependency in POM.xml, but it's still not being recognized. Maybe you can't pull down grails plugins like you would a standard maven reference? mvn install:install-file -DgroupId=org.grails -DartifactId=grails-hibernate -Dversion=1.1 -Dpackaging=zip -Dfile=%GRAILS_HOME%/plugins/grails-hibernate-1.1.zip I can manually setup the Grails webapp from the command-line, which creates that local ./plugins folder properly. This is a step in the right direction, so maybe the question is: how can I incorporate this goal into my POM? mvn grails:install-plugin -DpluginUrl=%GRAILS_HOME%/plugins/grails-hibernate-1.1.zip Here is a copy of my POM.xml file, which was generated using an archetype. <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.samples</groupId> <artifactId>sample-grails</artifactId> <packaging>war</packaging> <name>Sample Grails webapp</name> <properties> <sourceComplianceLevel>1.5</sourceComplianceLevel> </properties> <version>0.0.1-SNAPSHOT</version> <dependencies> <dependency> <groupId>org.grails</groupId> <artifactId>grails-crud</artifactId> <version>1.1</version> </dependency> <dependency> <groupId>org.grails</groupId> <artifactId>grails-gorm</artifactId> <version>1.1</version> </dependency> <dependency> <groupId>opensymphony</groupId> <artifactId>oscache</artifactId> <version>2.4</version> <exclusions> <exclusion> <groupId>commons-logging</groupId> <artifactId>commons-logging</artifactId> </exclusion> <exclusion> <groupId>javax.jms</groupId> <artifactId>jms</artifactId> </exclusion> <exclusion> <groupId>javax.servlet</groupId> <artifactId>servlet-api</artifactId> </exclusion> </exclusions> </dependency> <dependency> <groupId>hsqldb</groupId> <artifactId>hsqldb</artifactId> <version>1.8.0.7</version> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> <version>1.5.6</version> <scope>runtime</scope> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>jstl</artifactId> <version>1.2</version> </dependency> <!-- <dependency> <groupId>org.grails</groupId> <artifactId>grails-hibernate</artifactId> <version>1.1</version> <type>zip</type> </dependency> --> </dependencies> <build> <pluginManagement /> <plugins> <plugin> <groupId>org.grails</groupId> <artifactId>grails-maven-plugin</artifactId> <version>1.0</version> <extensions>true</extensions> <executions> <execution> <goals> <goal>init</goal> <goal>maven-clean</goal> <goal>validate</goal> <goal>config-directories</goal> <goal>maven-compile</goal> <goal>maven-test</goal> <goal>maven-war</goal> <goal>maven-functional-test</goal> </goals> </execution> </executions> </plugin> <plugin> <artifactId>maven-compiler-plugin</artifactId> <configuration> <source>${sourceComplianceLevel}</source> <target>${sourceComplianceLevel}</target> </configuration> </plugin> </plugins> </build> </project>

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  • Deadlock in SQL Server 2005! Two real-time bulk upserts are fighting. WHY?

    - by skimania
    Here's the scenario: I've got a table called MarketDataCurrent (MDC) that has live updating stock prices. I've got one process called 'LiveFeed' which reads prices streaming from the wire, queues up inserts, and uses a 'bulk upload to temp table then insert/update to MDC table.' (BulkUpsert) I've got another process which then reads this data, computes other data, and then saves the results back into the same table, using a similar BulkUpsert stored proc. Thirdly, there are a multitude of users running a C# Gui polling the MDC table and reading updates from it. Now, during the day when the data is changing rapidly, things run pretty smoothly, but then, after market hours, we've recently started seeing an increasing number of Deadlock exceptions coming out of the database, nowadays we see 10-20 a day. The imporant thing to note here is that these happen when the values are NOT changing. Here's all the relevant info: Table Def: CREATE TABLE [dbo].[MarketDataCurrent]( [MDID] [int] NOT NULL, [LastUpdate] [datetime] NOT NULL, [Value] [float] NOT NULL, [Source] [varchar](20) NULL, CONSTRAINT [PK_MarketDataCurrent] PRIMARY KEY CLUSTERED ( [MDID] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] - I've got a Sql Profiler Trace Running, catching the deadlocks, and here's what all the graphs look like. Process 258 is called the following 'BulkUpsert' stored proc, repeatedly, while 73 is calling the next one: ALTER proc [dbo].[MarketDataCurrent_BulkUpload] @updateTime datetime, @source varchar(10) as begin transaction update c with (rowlock) set LastUpdate = getdate(), Value = t.Value, Source = @source from MarketDataCurrent c INNER JOIN #MDTUP t ON c.MDID = t.mdid where c.lastUpdate < @updateTime and c.mdid not in (select mdid from MarketData where LiveFeedTicker is not null and PriceSource like 'LiveFeed.%') and c.value <> t.value insert into MarketDataCurrent with (rowlock) select MDID, getdate(), Value, @source from #MDTUP where mdid not in (select mdid from MarketDataCurrent with (nolock)) and mdid not in (select mdid from MarketData where LiveFeedTicker is not null and PriceSource like 'LiveFeed.%') commit And the other one: ALTER PROCEDURE [dbo].[MarketDataCurrent_LiveFeedUpload] AS begin transaction -- Update existing mdid UPDATE c WITH (ROWLOCK) SET LastUpdate = t.LastUpdate, Value = t.Value, Source = t.Source FROM MarketDataCurrent c INNER JOIN #TEMPTABLE2 t ON c.MDID = t.mdid; -- Insert new MDID INSERT INTO MarketDataCurrent with (ROWLOCK) SELECT * FROM #TEMPTABLE2 WHERE MDID NOT IN (SELECT MDID FROM MarketDataCurrent with (NOLOCK)) -- Clean up the temp table DELETE #TEMPTABLE2 commit To clarify, those Temp Tables are being created by the C# code on the same connection and are populated using the C# SqlBulkCopy class. To me it looks like it's deadlocking on the PK of the table, so I tried removing that PK and switching to a Unique Constraint instead but that increased the number of deadlocks 10-fold. I'm totally lost as to what to do about this situation and am open to just about any suggestion. HELP!! In response to the request for the XDL, here it is: <deadlock-list> <deadlock victim="processc19978"> <process-list> <process id="processaf0b68" taskpriority="0" logused="0" waitresource="KEY: 6:72057594090487808 (d900ed5a6cc6)" waittime="718" ownerId="1102128174" transactionname="user_transaction" lasttranstarted="2010-06-11T16:30:44.750" XDES="0xffffffff817f9a40" lockMode="U" schedulerid="3" kpid="8228" status="suspended" spid="73" sbid="0" ecid="0" priority="0" transcount="2" lastbatchstarted="2010-06-11T16:30:44.750" lastbatchcompleted="2010-06-11T16:30:44.750" clientapp=".Net SqlClient Data Provider" hostname="RISKAPPS_VM" hostpid="3836" loginname="RiskOpt" isolationlevel="read committed (2)" xactid="1102128174" currentdb="6" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056"> <executionStack> <frame procname="MKP_RISKDB.dbo.MarketDataCurrent_BulkUpload" line="28" stmtstart="1062" stmtend="1720" sqlhandle="0x03000600a28e5e4ef4fd8e00849d00000100000000000000"> UPDATE c WITH (ROWLOCK) SET LastUpdate = getdate(), Value = t.Value, Source = @source FROM MarketDataCurrent c INNER JOIN #MDTUP t ON c.MDID = t.mdid WHERE c.lastUpdate &lt; @updateTime and c.mdid not in (select mdid from MarketData where BloombergTicker is not null and PriceSource like &apos;Blbg.%&apos;) and c.value &lt;&gt; t.value </frame> <frame procname="adhoc" line="1" stmtstart="88" sqlhandle="0x01000600c1653d0598706ca7000000000000000000000000"> exec MarketDataCurrent_BulkUpload @clearBefore, @source </frame> <frame procname="unknown" line="1" sqlhandle="0x000000000000000000000000000000000000000000000000"> unknown </frame> </executionStack> <inputbuf> (@clearBefore datetime,@source nvarchar(10))exec MarketDataCurrent_BulkUpload @clearBefore, @source </inputbuf> </process> <process id="processc19978" taskpriority="0" logused="0" waitresource="KEY: 6:72057594090487808 (74008e31572b)" waittime="718" ownerId="1102128228" transactionname="user_transaction" lasttranstarted="2010-06-11T16:30:44.780" XDES="0x380be9d8" lockMode="U" schedulerid="5" kpid="8464" status="suspended" spid="248" sbid="0" ecid="0" priority="0" transcount="2" lastbatchstarted="2010-06-11T16:30:44.780" lastbatchcompleted="2010-06-11T16:30:44.780" clientapp=".Net SqlClient Data Provider" hostname="RISKBBG_VM" hostpid="4480" loginname="RiskOpt" isolationlevel="read committed (2)" xactid="1102128228" currentdb="6" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056"> <executionStack> <frame procname="MKP_RISKDB.dbo.MarketDataCurrentBlbgRtUpload" line="14" stmtstart="840" stmtend="1220" sqlhandle="0x03000600005f9d24c8878f00849d00000100000000000000"> UPDATE c WITH (ROWLOCK) SET LastUpdate = t.LastUpdate, Value = t.Value, Source = t.Source FROM MarketDataCurrent c INNER JOIN #TEMPTABLE2 t ON c.MDID = t.mdid; -- Insert new MDID </frame> <frame procname="adhoc" line="1" sqlhandle="0x010006004a58132228bf8d73000000000000000000000000"> MarketDataCurrentBlbgRtUpload </frame> </executionStack> <inputbuf> MarketDataCurrentBlbgRtUpload </inputbuf> </process> </process-list> <resource-list> <keylock hobtid="72057594090487808" dbid="6" objectname="MKP_RISKDB.dbo.MarketDataCurrent" indexname="PK_MarketDataCurrent" id="lock5ba77b00" mode="U" associatedObjectId="72057594090487808"> <owner-list> <owner id="processc19978" mode="U"/> </owner-list> <waiter-list> <waiter id="processaf0b68" mode="U" requestType="wait"/> </waiter-list> </keylock> <keylock hobtid="72057594090487808" dbid="6" objectname="MKP_RISKDB.dbo.MarketDataCurrent" indexname="PK_MarketDataCurrent" id="lock65dca340" mode="U" associatedObjectId="72057594090487808"> <owner-list> <owner id="processaf0b68" mode="U"/> </owner-list> <waiter-list> <waiter id="processc19978" mode="U" requestType="wait"/> </waiter-list> </keylock> </resource-list> </deadlock> </deadlock-list>

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  • Create Downloadable CSV File from PHP Script

    - by Aphex22
    How would I create a formatted version of the following PHP script as a downloadable CSV file from the code below (1.0) At the moment the fputcsv function is currently dumping the unparsed PHP/HTML code into a CSV file. This is incorrect. The downloaded CSV file should contain the columns and rows generated from the code at (1.0) as shown in the image link below. I've tried using the following code at the top of the PHP file: // output headers so that the file is downloaded rather than displayed header('Content-Type: text/csv; charset=utf-8'); header('Content-Disposition: attachment; filename=amazon.csv'); // create a file pointer connected to the output stream $output = fopen('php://output', 'w'); $mysql_hostname = ""; $mysql_user = ""; $mysql_password = ""; $mysql_database = ""; $bd = mysql_connect($mysql_hostname, $mysql_user, $mysql_password) or die("Could not connect database"); mysql_select_db($mysql_database, $bd) or die("Could not select database"); $sql = "select * from product WHERE on_amazon = 'on' AND active = 'on'"; $result = mysql_query($sql) or die ( mysql_error() ); // loop over the rows, outputting them while ($sql_result = mysql_fetch_assoc($sql)) fputcsv($output, $sql_result); 1.0 The start of the code outputs the column headings for the CSV file: // set headers echo " item_sku, external_product_id, external_product_id_type, item_name, brand_name, manufacturer, product_description, feed_product_type, update_delete, part_number, model, standard_price, list_price, currency, quantity, product_tax_code, product_site_launch_date, merchant_release_date, restock_date ... <br>"; And then follows PHP script for the column values // load all stock while ($line = mysql_fetch_assoc($result) ) { ?> <?php $size_suffix = array ("",'_chain','_con_b','_con_c'); $arrayLength = count ($size_suffix); for($y=0;$y<$arrayLength;$y++) { //Possible size array to loop through when checking quantity $con_size = array (36,365,37,375,38,385,39,395,40,405,41,415,42,425,43,435,44,445,45,455,46,465,47,475,48,485); $arrlength=count($con_size); for($x=0;$x<$arrlength;$x++) { // check if size is available if($line['quantity_c_size_'.$con_size[$x].$size_suffix[$y]] > 0 ) { ?> <!-- item sku --> <?=$line['product_id']?>, <!-- external product id --> <?=$line['code_size_'.$con_size[$x].'']?>, <? // external product id type $barcode = $line['code_size_'.$con_size[$x]]; $trim_barcode = trim($barcode); $count = strlen($trim_barcode); if ($count == 12) { echo "UPC"; } if ($count == 13) { echo "EAN"; } elseif ($count < 12) { echo " "; } ?>, <!-- item name --> <?=$line['title']?>, <? // brand_name $brand = $line['jys_brand']; echo ucfirst($brand); ?>, <? // manufacturer $brand = $line['jys_brand']; echo ucfirst($brand); ?>, <!-- product description --> <?=preg_replace('/[^\da-z]/i', ' ', $line['amazon_desc']) ?>, <!-- feed product type --> Shoes, , , , <!-- standard price --> <?=$line['price']?>, , <!-- currency --> GBP, <!-- quantity --> <?=$line['quantity_size_'.$con_size[$x].$size_suffix[$y]]?>, , <!-- product site launch date --> <?=$line['added_y']?>-<?=$line['added_m']?>-<?=$line['added_d']?>, <!-- merchat release date --> <?=$line['added_y']?>-<?=$line['added_m']?>-<?=$line['added_d']?>, , , , , <!-- item package quantity --> 1, , , , , <!-- fulfillment latency --> 2, <!-- max aggregate ship quantity --> 1, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , <!-- main image url, url1, url2, url3 --> http://www.getashoe.co.uk/full/<?=$line['product_id']?>_1.jpg, http://www.getashoe.co.uk/full/<?=$line['product_id']?>_2.jpg, http://www.getashoe.co.uk/full/<?=$line['product_id']?>_3.jpg, http://www.getashoe.co.uk/full/<?=$line['product_id']?>_4.jpg, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , <!-- heel height --> <?=$line['heel']?>, , , , , , , , , , , <!-- colour name --> <?=$line['colour']?>, <!-- colour map --> <? $colour = preg_replace('/[()]/i', ' ', $line['colour']); if (preg_match( '/[\/].*/i', $colour)) { echo 'Multicolour'; } if (preg_match( '/off.*/i', $colour)) { echo 'Off-White'; } elseif( preg_match( '/white.*/i', $colour)) { echo 'White'; } elseif( preg_match( '/moro.*/i', $colour)) { echo 'Brown'; } elseif( preg_match( '/morado.*/i', $colour)) { echo 'Purple'; } elseif( preg_match( '/cream.*/i', $colour)) { echo 'Off-White'; } elseif( preg_match( '/pewter.*/i', $colour)) { echo 'Silver'; } elseif( preg_match( '/yellow.*/i', $colour)) { echo 'Yellow'; } elseif( preg_match( '/camel.*/i', $colour)) { echo 'Beige'; } elseif( preg_match( '/navy.*/i', $colour)) { echo 'Blue'; } elseif( preg_match( '/tan.*/i', $colour)) { echo 'Brown'; } elseif( preg_match( '/rainbow.*/i', $colour)) { echo 'Multicolour'; } elseif( preg_match( '/orange.*/i', $colour)) { echo 'Orange'; } elseif( preg_match( '/leopard.*/i', $colour)) { echo 'Multicolour'; } elseif( preg_match( '/red.*/i', $colour)) { echo 'Red'; } elseif( preg_match( '/pink.*/i', $colour)) { echo 'Pink'; } elseif( preg_match( '/purple.*/i', $colour)) { echo 'Purple'; } elseif( preg_match( '/blue.*/i', $colour)) { echo 'Blue'; } elseif( preg_match( '/green.*/i', $colour)) { echo 'Green'; } elseif( preg_match( '/brown.*/i', $colour)) { echo 'Brown'; } elseif( preg_match( '/grey.*/i', $colour)) { echo 'Grey'; } elseif( preg_match( '/black.*/i', $colour)) { echo 'Black'; } elseif( preg_match( '/gold.*/i', $colour)) { echo 'Gold'; } elseif( preg_match( '/silver.*/i', $colour)) { echo 'Silver'; } elseif( preg_match( '/multi.*/i', $colour)) { echo 'Multicolour'; } elseif( preg_match( '/beige.*/i', $colour)) { echo 'Beige'; } elseif( preg_match( '/nude.*/i', $colour)) { echo 'Beige'; } ?>, <!-- size name --> <? echo $con_size[$x];?>, <!-- size map --> <? if ($con_size[$x] == 36) { echo "3 UK"; } elseif ($con_size[$x] == 37 ) { echo "4 UK"; } elseif ($con_size[$x] == 38) { echo "5 UK"; } elseif ($con_size[$x] == 39 ) { echo "6 UK"; } elseif ($con_size[$x] == 40 ) { echo "7 UK"; } elseif ($con_size[$x] == 41) { echo "8 UK"; } elseif ($con_size[$x] == 42) { echo "9 UK"; } elseif ($con_size[$x] == 43) { echo "10 UK"; } elseif ($con_size[$x] == 44 ) { echo "11 UK"; } elseif ($con_size[$x] == 45 ) { echo "12 UK"; } elseif ($con_size[$x] == 46 ) { echo "13 UK"; } elseif ($con_size[$x] == 47 ) { echo "14 UK"; } elseif ($con_size[$x] == 48 ) { echo "15 UK"; } elseif ($con_size[$x] == 365) { echo "3.5 UK"; } elseif ($con_size[$x] == 375 ) { echo "4.5 UK"; } elseif ($con_size[$x] == 385) { echo "5.5 UK"; } elseif ($con_size[$x] == 395 ) { echo "6.5 UK"; } elseif ($con_size[$x] == 405 ) { echo "7.5 UK"; } elseif ($con_size[$x] == 415) { echo "8.5 UK"; } elseif ($con_size[$x] == 425) { echo "9.5 UK"; } elseif ($con_size[$x] == 435) { echo "10.5 UK"; } elseif ($con_size[$x] == 445 ) { echo "11.5 UK"; } elseif ($con_size[$x] == 455 ) { echo "12.5 UK"; } elseif ($con_size[$x] == 465 ) { echo "13.5 UK"; } elseif ($con_size[$x] == 475 ) { echo "14.5 UK"; } elseif ($con_size[$x] == 485 ) { echo "15.5 UK"; } ?>, <br> <? // finish checking if size is available } } } ?> I've included an image of how the CSV file should appear. https://i.imgur.com/ZU3IFer.png Any help would be great.

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  • Custom ASP.NET Routing to an HttpHandler

    - by Rick Strahl
    As of version 4.0 ASP.NET natively supports routing via the now built-in System.Web.Routing namespace. Routing features are automatically integrated into the HtttpRuntime via a few custom interfaces. New Web Forms Routing Support In ASP.NET 4.0 there are a host of improvements including routing support baked into Web Forms via a RouteData property available on the Page class and RouteCollection.MapPageRoute() route handler that makes it easy to route to Web forms. To map ASP.NET Page routes is as simple as setting up the routes with MapPageRoute:protected void Application_Start(object sender, EventArgs e) { RegisterRoutes(RouteTable.Routes); } void RegisterRoutes(RouteCollection routes) { routes.MapPageRoute("StockQuote", "StockQuote/{symbol}", "StockQuote.aspx"); routes.MapPageRoute("StockQuotes", "StockQuotes/{symbolList}", "StockQuotes.aspx"); } and then accessing the route data in the page you can then use the new Page class RouteData property to retrieve the dynamic route data information:public partial class StockQuote1 : System.Web.UI.Page { protected StockQuote Quote = null; protected void Page_Load(object sender, EventArgs e) { string symbol = RouteData.Values["symbol"] as string; StockServer server = new StockServer(); Quote = server.GetStockQuote(symbol); // display stock data in Page View } } Simple, quick and doesn’t require much explanation. If you’re using WebForms most of your routing needs should be served just fine by this simple mechanism. Kudos to the ASP.NET team for putting this in the box and making it easy! How Routing Works To handle Routing in ASP.NET involves these steps: Registering Routes Creating a custom RouteHandler to retrieve an HttpHandler Attaching RouteData to your HttpHandler Picking up Route Information in your Request code Registering routes makes ASP.NET aware of the Routes you want to handle via the static RouteTable.Routes collection. You basically add routes to this collection to let ASP.NET know which URL patterns it should watch for. You typically hook up routes off a RegisterRoutes method that fires in Application_Start as I did in the example above to ensure routes are added only once when the application first starts up. When you create a route, you pass in a RouteHandler instance which ASP.NET caches and reuses as routes are matched. Once registered ASP.NET monitors the routes and if a match is found just prior to the HttpHandler instantiation, ASP.NET uses the RouteHandler registered for the route and calls GetHandler() on it to retrieve an HttpHandler instance. The RouteHandler.GetHandler() method is responsible for creating an instance of an HttpHandler that is to handle the request and – if necessary – to assign any additional custom data to the handler. At minimum you probably want to pass the RouteData to the handler so the handler can identify the request based on the route data available. To do this you typically add  a RouteData property to your handler and then assign the property from the RouteHandlers request context. This is essentially how Page.RouteData comes into being and this approach should work well for any custom handler implementation that requires RouteData. It’s a shame that ASP.NET doesn’t have a top level intrinsic object that’s accessible off the HttpContext object to provide route data more generically, but since RouteData is directly tied to HttpHandlers and not all handlers support it it might cause some confusion of when it’s actually available. Bottom line is that if you want to hold on to RouteData you have to assign it to a custom property of the handler or else pass it to the handler via Context.Items[] object that can be retrieved on an as needed basis. It’s important to understand that routing is hooked up via RouteHandlers that are responsible for loading HttpHandler instances. RouteHandlers are invoked for every request that matches a route and through this RouteHandler instance the Handler gains access to the current RouteData. Because of this logic it’s important to understand that Routing is really tied to HttpHandlers and not available prior to handler instantiation, which is pretty late in the HttpRuntime’s request pipeline. IOW, Routing works with Handlers but not with earlier in the pipeline within Modules. Specifically ASP.NET calls RouteHandler.GetHandler() from the PostResolveRequestCache HttpRuntime pipeline event. Here’s the call stack at the beginning of the GetHandler() call: which fires just before handler resolution. Non-Page Routing – You need to build custom RouteHandlers If you need to route to a custom Http Handler or other non-Page (and non-MVC) endpoint in the HttpRuntime, there is no generic mapping support available. You need to create a custom RouteHandler that can manage creating an instance of an HttpHandler that is fired in response to a routed request. Depending on what you are doing this process can be simple or fairly involved as your code is responsible based on the route data provided which handler to instantiate, and more importantly how to pass the route data on to the Handler. Luckily creating a RouteHandler is easy by implementing the IRouteHandler interface which has only a single GetHttpHandler(RequestContext context) method. In this method you can pick up the requestContext.RouteData, instantiate the HttpHandler of choice, and assign the RouteData to it. Then pass back the handler and you’re done.Here’s a simple example of GetHttpHandler() method that dynamically creates a handler based on a passed in Handler type./// <summary> /// Retrieves an Http Handler based on the type specified in the constructor /// </summary> /// <param name="requestContext"></param> /// <returns></returns> IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; // If we're dealing with a Callback Handler // pass the RouteData for this route to the Handler if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; } Note that this code checks for a specific type of handler and if it matches assigns the RouteData to this handler. This is optional but quite a common scenario if you want to work with RouteData. If the handler you need to instantiate isn’t under your control but you still need to pass RouteData to Handler code, an alternative is to pass the RouteData via the HttpContext.Items collection:IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; requestContext.HttpContext.Items["RouteData"] = requestContext.RouteData; return handler; } The code in the handler implementation can then pick up the RouteData from the context collection as needed:RouteData routeData = HttpContext.Current.Items["RouteData"] as RouteData This isn’t as clean as having an explicit RouteData property, but it does have the advantage that the route data is visible anywhere in the Handler’s code chain. It’s definitely preferable to create a custom property on your handler, but the Context work-around works in a pinch when you don’t’ own the handler code and have dynamic code executing as part of the handler execution. An Example of a Custom RouteHandler: Attribute Based Route Implementation In this post I’m going to discuss a custom routine implementation I built for my CallbackHandler class in the West Wind Web & Ajax Toolkit. CallbackHandler can be very easily used for creating AJAX, REST and POX requests following RPC style method mapping. You can pass parameters via URL query string, POST data or raw data structures, and you can retrieve results as JSON, XML or raw string/binary data. It’s a quick and easy way to build service interfaces with no fuss. As a quick review here’s how CallbackHandler works: You create an Http Handler that derives from CallbackHandler You implement methods that have a [CallbackMethod] Attribute and that’s it. Here’s an example of an CallbackHandler implementation in an ashx.cs based handler:// RestService.ashx.cs public class RestService : CallbackHandler { [CallbackMethod] public StockQuote GetStockQuote(string symbol) { StockServer server = new StockServer(); return server.GetStockQuote(symbol); } [CallbackMethod] public StockQuote[] GetStockQuotes(string symbolList) { StockServer server = new StockServer(); string[] symbols = symbolList.Split(new char[2] { ',',';' },StringSplitOptions.RemoveEmptyEntries); return server.GetStockQuotes(symbols); } } CallbackHandler makes it super easy to create a method on the server, pass data to it via POST, QueryString or raw JSON/XML data, and then retrieve the results easily back in various formats. This works wonderful and I’ve used these tools in many projects for myself and with clients. But one thing missing has been the ability to create clean URLs. Typical URLs looked like this: http://www.west-wind.com/WestwindWebToolkit/samples/Rest/StockService.ashx?Method=GetStockQuote&symbol=msfthttp://www.west-wind.com/WestwindWebToolkit/samples/Rest/StockService.ashx?Method=GetStockQuotes&symbolList=msft,intc,gld,slw,mwe&format=xml which works and is clear enough, but also clearly very ugly. It would be much nicer if URLs could look like this: http://www.west-wind.com//WestwindWebtoolkit/Samples/StockQuote/msfthttp://www.west-wind.com/WestwindWebtoolkit/Samples/StockQuotes/msft,intc,gld,slw?format=xml (the Virtual Root in this sample is WestWindWebToolkit/Samples and StockQuote/{symbol} is the route)(If you use FireFox try using the JSONView plug-in make it easier to view JSON content) So, taking a clue from the WCF REST tools that use RouteUrls I set out to create a way to specify RouteUrls for each of the endpoints. The change made basically allows changing the above to: [CallbackMethod(RouteUrl="RestService/StockQuote/{symbol}")] public StockQuote GetStockQuote(string symbol) { StockServer server = new StockServer(); return server.GetStockQuote(symbol); } [CallbackMethod(RouteUrl = "RestService/StockQuotes/{symbolList}")] public StockQuote[] GetStockQuotes(string symbolList) { StockServer server = new StockServer(); string[] symbols = symbolList.Split(new char[2] { ',',';' },StringSplitOptions.RemoveEmptyEntries); return server.GetStockQuotes(symbols); } where a RouteUrl is specified as part of the Callback attribute. And with the changes made with RouteUrls I can now get URLs like the second set shown earlier. So how does that work? Let’s find out… How to Create Custom Routes As mentioned earlier Routing is made up of several steps: Creating a custom RouteHandler to create HttpHandler instances Mapping the actual Routes to the RouteHandler Retrieving the RouteData and actually doing something useful with it in the HttpHandler In the CallbackHandler routing example above this works out to something like this: Create a custom RouteHandler that includes a property to track the method to call Set up the routes using Reflection against the class Looking for any RouteUrls in the CallbackMethod attribute Add a RouteData property to the CallbackHandler so we can access the RouteData in the code of the handler Creating a Custom Route Handler To make the above work I created a custom RouteHandler class that includes the actual IRouteHandler implementation as well as a generic and static method to automatically register all routes marked with the [CallbackMethod(RouteUrl="…")] attribute. Here’s the code:/// <summary> /// Route handler that can create instances of CallbackHandler derived /// callback classes. The route handler tracks the method name and /// creates an instance of the service in a predictable manner /// </summary> /// <typeparam name="TCallbackHandler">CallbackHandler type</typeparam> public class CallbackHandlerRouteHandler : IRouteHandler { /// <summary> /// Method name that is to be called on this route. /// Set by the automatically generated RegisterRoutes /// invokation. /// </summary> public string MethodName { get; set; } /// <summary> /// The type of the handler we're going to instantiate. /// Needed so we can semi-generically instantiate the /// handler and call the method on it. /// </summary> public Type CallbackHandlerType { get; set; } /// <summary> /// Constructor to pass in the two required components we /// need to create an instance of our handler. /// </summary> /// <param name="methodName"></param> /// <param name="callbackHandlerType"></param> public CallbackHandlerRouteHandler(string methodName, Type callbackHandlerType) { MethodName = methodName; CallbackHandlerType = callbackHandlerType; } /// <summary> /// Retrieves an Http Handler based on the type specified in the constructor /// </summary> /// <param name="requestContext"></param> /// <returns></returns> IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; // If we're dealing with a Callback Handler // pass the RouteData for this route to the Handler if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; } /// <summary> /// Generic method to register all routes from a CallbackHandler /// that have RouteUrls defined on the [CallbackMethod] attribute /// </summary> /// <typeparam name="TCallbackHandler">CallbackHandler Type</typeparam> /// <param name="routes"></param> public static void RegisterRoutes<TCallbackHandler>(RouteCollection routes) { // find all methods var methods = typeof(TCallbackHandler).GetMethods(BindingFlags.Instance | BindingFlags.Public); foreach (var method in methods) { var attrs = method.GetCustomAttributes(typeof(CallbackMethodAttribute), false); if (attrs.Length < 1) continue; CallbackMethodAttribute attr = attrs[0] as CallbackMethodAttribute; if (string.IsNullOrEmpty(attr.RouteUrl)) continue; // Add the route routes.Add(method.Name, new Route(attr.RouteUrl, new CallbackHandlerRouteHandler(method.Name, typeof(TCallbackHandler)))); } } } The RouteHandler implements IRouteHandler, and its responsibility via the GetHandler method is to create an HttpHandler based on the route data. When ASP.NET calls GetHandler it passes a requestContext parameter which includes a requestContext.RouteData property. This parameter holds the current request’s route data as well as an instance of the current RouteHandler. If you look at GetHttpHandler() you can see that the code creates an instance of the handler we are interested in and then sets the RouteData property on the handler. This is how you can pass the current request’s RouteData to the handler. The RouteData object also has a  RouteData.RouteHandler property that is also available to the Handler later, which is useful in order to get additional information about the current route. In our case here the RouteHandler includes a MethodName property that identifies the method to execute in the handler since that value no longer comes from the URL so we need to figure out the method name some other way. The method name is mapped explicitly when the RouteHandler is created and here the static method that auto-registers all CallbackMethods with RouteUrls sets the method name when it creates the routes while reflecting over the methods (more on this in a minute). The important point here is that you can attach additional properties to the RouteHandler and you can then later access the RouteHandler and its properties later in the Handler to pick up these custom values. This is a crucial feature in that the RouteHandler serves in passing additional context to the handler so it knows what actions to perform. The automatic route registration is handled by the static RegisterRoutes<TCallbackHandler> method. This method is generic and totally reusable for any CallbackHandler type handler. To register a CallbackHandler and any RouteUrls it has defined you simple use code like this in Application_Start (or other application startup code):protected void Application_Start(object sender, EventArgs e) { // Register Routes for RestService CallbackHandlerRouteHandler.RegisterRoutes<RestService>(RouteTable.Routes); } If you have multiple CallbackHandler style services you can make multiple calls to RegisterRoutes for each of the service types. RegisterRoutes internally uses reflection to run through all the methods of the Handler, looking for CallbackMethod attributes and whether a RouteUrl is specified. If it is a new instance of a CallbackHandlerRouteHandler is created and the name of the method and the type are set. routes.Add(method.Name,           new Route(attr.RouteUrl, new CallbackHandlerRouteHandler(method.Name, typeof(TCallbackHandler) )) ); While the routing with CallbackHandlerRouteHandler is set up automatically for all methods that use the RouteUrl attribute, you can also use code to hook up those routes manually and skip using the attribute. The code for this is straightforward and just requires that you manually map each individual route to each method you want a routed: protected void Application_Start(objectsender, EventArgs e){    RegisterRoutes(RouteTable.Routes);}void RegisterRoutes(RouteCollection routes) { routes.Add("StockQuote Route",new Route("StockQuote/{symbol}",                     new CallbackHandlerRouteHandler("GetStockQuote",typeof(RestService) ) ) );     routes.Add("StockQuotes Route",new Route("StockQuotes/{symbolList}",                     new CallbackHandlerRouteHandler("GetStockQuotes",typeof(RestService) ) ) );}I think it’s clearly easier to have CallbackHandlerRouteHandler.RegisterRoutes() do this automatically for you based on RouteUrl attributes, but some people have a real aversion to attaching logic via attributes. Just realize that the option to manually create your routes is available as well. Using the RouteData in the Handler A RouteHandler’s responsibility is to create an HttpHandler and as mentioned earlier, natively IHttpHandler doesn’t have any support for RouteData. In order to utilize RouteData in your handler code you have to pass the RouteData to the handler. In my CallbackHandlerRouteHandler when it creates the HttpHandler instance it creates the instance and then assigns the custom RouteData property on the handler:IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; Again this only works if you actually add a RouteData property to your handler explicitly as I did in my CallbackHandler implementation:/// <summary> /// Optionally store RouteData on this handler /// so we can access it internally /// </summary> public RouteData RouteData {get; set; } and the RouteHandler needs to set it when it creates the handler instance. Once you have the route data in your handler you can access Route Keys and Values and also the RouteHandler. Since my RouteHandler has a custom property for the MethodName to retrieve it from within the handler I can do something like this now to retrieve the MethodName (this example is actually not in the handler but target is an instance pass to the processor): // check for Route Data method name if (target is CallbackHandler) { var routeData = ((CallbackHandler)target).RouteData; if (routeData != null) methodToCall = ((CallbackHandlerRouteHandler)routeData.RouteHandler).MethodName; } When I need to access the dynamic values in the route ( symbol in StockQuote/{symbol}) I can retrieve it easily with the Values collection (RouteData.Values["symbol"]). In my CallbackHandler processing logic I’m basically looking for matching parameter names to Route parameters: // look for parameters in the routeif(routeData != null){    string parmString = routeData.Values[parameter.Name] as string;    adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType);} And with that we’ve come full circle. We’ve created a custom RouteHandler() that passes the RouteData to the handler it creates. We’ve registered our routes to use the RouteHandler, and we’ve utilized the route data in our handler. For completeness sake here’s the routine that executes a method call based on the parameters passed in and one of the options is to retrieve the inbound parameters off RouteData (as well as from POST data or QueryString parameters):internal object ExecuteMethod(string method, object target, string[] parameters, CallbackMethodParameterType paramType, ref CallbackMethodAttribute callbackMethodAttribute) { HttpRequest Request = HttpContext.Current.Request; object Result = null; // Stores parsed parameters (from string JSON or QUeryString Values) object[] adjustedParms = null; Type PageType = target.GetType(); MethodInfo MI = PageType.GetMethod(method, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic); if (MI == null) throw new InvalidOperationException("Invalid Server Method."); object[] methods = MI.GetCustomAttributes(typeof(CallbackMethodAttribute), false); if (methods.Length < 1) throw new InvalidOperationException("Server method is not accessible due to missing CallbackMethod attribute"); if (callbackMethodAttribute != null) callbackMethodAttribute = methods[0] as CallbackMethodAttribute; ParameterInfo[] parms = MI.GetParameters(); JSONSerializer serializer = new JSONSerializer(); RouteData routeData = null; if (target is CallbackHandler) routeData = ((CallbackHandler)target).RouteData; int parmCounter = 0; adjustedParms = new object[parms.Length]; foreach (ParameterInfo parameter in parms) { // Retrieve parameters out of QueryString or POST buffer if (parameters == null) { // look for parameters in the route if (routeData != null) { string parmString = routeData.Values[parameter.Name] as string; adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType); } // GET parameter are parsed as plain string values - no JSON encoding else if (HttpContext.Current.Request.HttpMethod == "GET") { // Look up the parameter by name string parmString = Request.QueryString[parameter.Name]; adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType); } // POST parameters are treated as methodParameters that are JSON encoded else if (paramType == CallbackMethodParameterType.Json) //string newVariable = methodParameters.GetValue(parmCounter) as string; adjustedParms[parmCounter] = serializer.Deserialize(Request.Params["parm" + (parmCounter + 1).ToString()], parameter.ParameterType); else adjustedParms[parmCounter] = SerializationUtils.DeSerializeObject( Request.Params["parm" + (parmCounter + 1).ToString()], parameter.ParameterType); } else if (paramType == CallbackMethodParameterType.Json) adjustedParms[parmCounter] = serializer.Deserialize(parameters[parmCounter], parameter.ParameterType); else adjustedParms[parmCounter] = SerializationUtils.DeSerializeObject(parameters[parmCounter], parameter.ParameterType); parmCounter++; } Result = MI.Invoke(target, adjustedParms); return Result; } The code basically uses Reflection to loop through all the parameters available on the method and tries to assign the parameters from RouteData, QueryString or POST variables. The parameters are converted into their appropriate types and then used to eventually make a Reflection based method call. What’s sweet is that the RouteData retrieval is just another option for dealing with the inbound data in this scenario and it adds exactly two lines of code plus the code to retrieve the MethodName I showed previously – a seriously low impact addition that adds a lot of extra value to this endpoint callback processing implementation. Debugging your Routes If you create a lot of routes it’s easy to run into Route conflicts where multiple routes have the same path and overlap with each other. This can be difficult to debug especially if you are using automatically generated routes like the routes created by CallbackHandlerRouteHandler.RegisterRoutes. Luckily there’s a tool that can help you out with this nicely. Phill Haack created a RouteDebugging tool you can download and add to your project. The easiest way to do this is to grab and add this to your project is to use NuGet (Add Library Package from your Project’s Reference Nodes):   which adds a RouteDebug assembly to your project. Once installed you can easily debug your routes with this simple line of code which needs to be installed at application startup:protected void Application_Start(object sender, EventArgs e) { CallbackHandlerRouteHandler.RegisterRoutes<StockService>(RouteTable.Routes); // Debug your routes RouteDebug.RouteDebugger.RewriteRoutesForTesting(RouteTable.Routes); } Any routed URL then displays something like this: The screen shows you your current route data and all the routes that are mapped along with a flag that displays which route was actually matched. This is useful – if you have any overlap of routes you will be able to see which routes are triggered – the first one in the sequence wins. This tool has saved my ass on a few occasions – and with NuGet now it’s easy to add it to your project in a few seconds and then remove it when you’re done. Routing Around Custom routing seems slightly complicated on first blush due to its disconnected components of RouteHandler, route registration and mapping of custom handlers. But once you understand the relationship between a RouteHandler, the RouteData and how to pass it to a handler, utilizing of Routing becomes a lot easier as you can easily pass context from the registration to the RouteHandler and through to the HttpHandler. The most important thing to understand when building custom routing solutions is to figure out how to map URLs in such a way that the handler can figure out all the pieces it needs to process the request. This can be via URL routing parameters and as I did in my example by passing additional context information as part of the RouteHandler instance that provides the proper execution context. In my case this ‘context’ was the method name, but it could be an actual static value like an enum identifying an operation or category in an application. Basically user supplied data comes in through the url and static application internal data can be passed via RouteHandler property values. Routing can make your application URLs easier to read by non-techie types regardless of whether you’re building Service type or REST applications, or full on Web interfaces. Routing in ASP.NET 4.0 makes it possible to create just about any extensionless URLs you can dream up and custom RouteHanmdler References Sample ProjectIncludes the sample CallbackHandler service discussed here along with compiled versionsof the Westwind.Web and Westwind.Utilities assemblies.  (requires .NET 4.0/VS 2010) West Wind Web Toolkit includes full implementation of CallbackHandler and the Routing Handler West Wind Web Toolkit Source CodeContains the full source code to the Westwind.Web and Westwind.Utilities assemblies usedin these samples. Includes the source described in the post.(Latest build in the Subversion Repository) CallbackHandler Source(Relevant code to this article tree in Westwind.Web assembly) JSONView FireFoxPluginA simple FireFox Plugin to easily view JSON data natively in FireFox.For IE you can use a registry hack to display JSON as raw text.© Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  AJAX  HTTP  

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  • Red Gate Coder interviews: Alex Davies

    - by Michael Williamson
    Alex Davies has been a software engineer at Red Gate since graduating from university, and is currently busy working on .NET Demon. We talked about tackling parallel programming with his actors framework, a scientific approach to debugging, and how JavaScript is going to affect the programming languages we use in years to come. So, if we start at the start, how did you get started in programming? When I was seven or eight, I was given a BBC Micro for Christmas. I had asked for a Game Boy, but my dad thought it would be better to give me a proper computer. For a year or so, I only played games on it, but then I found the user guide for writing programs in it. I gradually started doing more stuff on it and found it fun. I liked creating. As I went into senior school I continued to write stuff on there, trying to write games that weren’t very good. I got a real computer when I was fourteen and found ways to write BASIC on it. Visual Basic to start with, and then something more interesting than that. How did you learn to program? Was there someone helping you out? Absolutely not! I learnt out of a book, or by experimenting. I remember the first time I found a loop, I was like “Oh my God! I don’t have to write out the same line over and over and over again any more. It’s amazing!” When did you think this might be something that you actually wanted to do as a career? For a long time, I thought it wasn’t something that you would do as a career, because it was too much fun to be a career. I thought I’d do chemistry at university and some kind of career based on chemical engineering. And then I went to a careers fair at school when I was seventeen or eighteen, and it just didn’t interest me whatsoever. I thought “I could be a programmer, and there’s loads of money there, and I’m good at it, and it’s fun”, but also that I shouldn’t spoil my hobby. Now I don’t really program in my spare time any more, which is a bit of a shame, but I program all the rest of the time, so I can live with it. Do you think you learnt much about programming at university? Yes, definitely! I went into university knowing how to make computers do anything I wanted them to do. However, I didn’t have the language to talk about algorithms, so the algorithms course in my first year was massively important. Learning other language paradigms like functional programming was really good for breadth of understanding. Functional programming influences normal programming through design rather than actually using it all the time. I draw inspiration from it to write imperative programs which I think is actually becoming really fashionable now, but I’ve been doing it for ages. I did it first! There were also some courses on really odd programming languages, a bit of Prolog, a little bit of C. Having a little bit of each of those is something that I would have never done on my own, so it was important. And then there are knowledge-based courses which are about not programming itself but things that have been programmed like TCP. Those are really important for examples for how to approach things. Did you do any internships while you were at university? Yeah, I spent both of my summers at the same company. I thought I could code well before I went there. Looking back at the crap that I produced, it was only surpassed in its crappiness by all of the other code already in that company. I’m so much better at writing nice code now than I used to be back then. Was there just not a culture of looking after your code? There was, they just didn’t hire people for their abilities in that area. They hired people for raw IQ. The first indicator of it going wrong was that they didn’t have any computer scientists, which is a bit odd in a programming company. But even beyond that they didn’t have people who learnt architecture from anyone else. Most of them had started straight out of university, so never really had experience or mentors to learn from. There wasn’t the experience to draw from to teach each other. In the second half of my second internship, I was being given tasks like looking at new technologies and teaching people stuff. Interns shouldn’t be teaching people how to do their jobs! All interns are going to have little nuggets of things that you don’t know about, but they shouldn’t consistently be the ones who know the most. It’s not a good environment to learn. I was going to ask how you found working with people who were more experienced than you… When I reached Red Gate, I found some people who were more experienced programmers than me, and that was difficult. I’ve been coding since I was tiny. At university there were people who were cleverer than me, but there weren’t very many who were more experienced programmers than me. During my internship, I didn’t find anyone who I classed as being a noticeably more experienced programmer than me. So, it was a shock to the system to have valid criticisms rather than just formatting criticisms. However, Red Gate’s not so big on the actual code review, at least it wasn’t when I started. We did an entire product release and then somebody looked over all of the UI of that product which I’d written and say what they didn’t like. By that point, it was way too late and I’d disagree with them. Do you think the lack of code reviews was a bad thing? I think if there’s going to be any oversight of new people, then it should be continuous rather than chunky. For me I don’t mind too much, I could go out and get oversight if I wanted it, and in those situations I felt comfortable without it. If I was managing the new person, then maybe I’d be keener on oversight and then the right way to do it is continuously and in very, very small chunks. Have you had any significant projects you’ve worked on outside of a job? When I was a teenager I wrote all sorts of stuff. I used to write games, I derived how to do isomorphic projections myself once. I didn’t know what the word was so I couldn’t Google for it, so I worked it out myself. It was horrifically complicated. But it sort of tailed off when I started at university, and is now basically zero. If I do side-projects now, they tend to be work-related side projects like my actors framework, NAct, which I started in a down tools week. Could you explain a little more about NAct? It is a little C# framework for writing parallel code more easily. Parallel programming is difficult when you need to write to shared data. Sometimes parallel programming is easy because you don’t need to write to shared data. When you do need to access shared data, you could just have your threads pile in and do their work, but then you would screw up the data because the threads would trample on each other’s toes. You could lock, but locks are really dangerous if you’re using more than one of them. You get interactions like deadlocks, and that’s just nasty. Actors instead allows you to say this piece of data belongs to this thread of execution, and nobody else can read it. If you want to read it, then ask that thread of execution for a piece of it by sending a message, and it will send the data back by a message. And that avoids deadlocks as long as you follow some obvious rules about not making your actors sit around waiting for other actors to do something. There are lots of ways to write actors, NAct allows you to do it as if it was method calls on other objects, which means you get all the strong type-safety that C# programmers like. Do you think that this is suitable for the majority of parallel programming, or do you think it’s only suitable for specific cases? It’s suitable for most difficult parallel programming. If you’ve just got a hundred web requests which are all independent of each other, then I wouldn’t bother because it’s easier to just spin them up in separate threads and they can proceed independently of each other. But where you’ve got difficult parallel programming, where you’ve got multiple threads accessing multiple bits of data in multiple ways at different times, then actors is at least as good as all other ways, and is, I reckon, easier to think about. When you’re using actors, you presumably still have to write your code in a different way from you would otherwise using single-threaded code. You can’t use actors with any methods that have return types, because you’re not allowed to call into another actor and wait for it. If you want to get a piece of data out of another actor, then you’ve got to use tasks so that you can use “async” and “await” to await asynchronously for it. But other than that, you can still stick things in classes so it’s not too different really. Rather than having thousands of objects with mutable state, you can use component-orientated design, where there are only a few mutable classes which each have a small number of instances. Then there can be thousands of immutable objects. If you tend to do that anyway, then actors isn’t much of a jump. If I’ve already built my system without any parallelism, how hard is it to add actors to exploit all eight cores on my desktop? Usually pretty easy. If you can identify even one boundary where things look like messages and you have components where some objects live on one side and these other objects live on the other side, then you can have a granddaddy object on one side be an actor and it will parallelise as it goes across that boundary. Not too difficult. If we do get 1000-core desktop PCs, do you think actors will scale up? It’s hard. There are always in the order of twenty to fifty actors in my whole program because I tend to write each component as actors, and I tend to have one instance of each component. So this won’t scale to a thousand cores. What you can do is write data structures out of actors. I use dictionaries all over the place, and if you need a dictionary that is going to be accessed concurrently, then you could build one of those out of actors in no time. You can use queuing to marshal requests between different slices of the dictionary which are living on different threads. So it’s like a distributed hash table but all of the chunks of it are on the same machine. That means that each of these thousand processors has cached one small piece of the dictionary. I reckon it wouldn’t be too big a leap to start doing proper parallelism. Do you think it helps if actors get baked into the language, similarly to Erlang? Erlang is excellent in that it has thread-local garbage collection. C# doesn’t, so there’s a limit to how well C# actors can possibly scale because there’s a single garbage collected heap shared between all of them. When you do a global garbage collection, you’ve got to stop all of the actors, which is seriously expensive, whereas in Erlang garbage collections happen per-actor, so they’re insanely cheap. However, Erlang deviated from all the sensible language design that people have used recently and has just come up with crazy stuff. You can definitely retrofit thread-local garbage collection to .NET, and then it’s quite well-suited to support actors, even if it’s not baked into the language. Speaking of language design, do you have a favourite programming language? I’ll choose a language which I’ve never written before. I like the idea of Scala. It sounds like C#, only with some of the niggles gone. I enjoy writing static types. It means you don’t have to writing tests so much. When you say it doesn’t have some of the niggles? C# doesn’t allow the use of a property as a method group. It doesn’t have Scala case classes, or sum types, where you can do a switch statement and the compiler checks that you’ve checked all the cases, which is really useful in functional-style programming. Pattern-matching, in other words. That’s actually the major niggle. C# is pretty good, and I’m quite happy with C#. And what about going even further with the type system to remove the need for tests to something like Haskell? Or is that a step too far? I’m quite a pragmatist, I don’t think I could deal with trying to write big systems in languages with too few other users, especially when learning how to structure things. I just don’t know anyone who can teach me, and the Internet won’t teach me. That’s the main reason I wouldn’t use it. If I turned up at a company that writes big systems in Haskell, I would have no objection to that, but I wouldn’t instigate it. What about things in C#? For instance, there’s contracts in C#, so you can try to statically verify a bit more about your code. Do you think that’s useful, or just not worthwhile? I’ve not really tried it. My hunch is that it needs to be built into the language and be quite mathematical for it to work in real life, and that doesn’t seem to have ended up true for C# contracts. I don’t think anyone who’s tried them thinks they’re any good. I might be wrong. On a slightly different note, how do you like to debug code? I think I’m quite an odd debugger. I use guesswork extremely rarely, especially if something seems quite difficult to debug. I’ve been bitten spending hours and hours on guesswork and not being scientific about debugging in the past, so now I’m scientific to a fault. What I want is to see the bug happening in the debugger, to step through the bug happening. To watch the program going from a valid state to an invalid state. When there’s a bug and I can’t work out why it’s happening, I try to find some piece of evidence which places the bug in one section of the code. From that experiment, I binary chop on the possible causes of the bug. I suppose that means binary chopping on places in the code, or binary chopping on a stage through a processing cycle. Basically, I’m very stupid about how I debug. I won’t make any guesses, I won’t use any intuition, I will only identify the experiment that’s going to binary chop most effectively and repeat rather than trying to guess anything. I suppose it’s quite top-down. Is most of the time then spent in the debugger? Absolutely, if at all possible I will never debug using print statements or logs. I don’t really hold much stock in outputting logs. If there’s any bug which can be reproduced locally, I’d rather do it in the debugger than outputting logs. And with SmartAssembly error reporting, there’s not a lot that can’t be either observed in an error report and just fixed, or reproduced locally. And in those other situations, maybe I’ll use logs. But I hate using logs. You stare at the log, trying to guess what’s going on, and that’s exactly what I don’t like doing. You have to just look at it and see does this look right or wrong. We’ve covered how you get to grip with bugs. How do you get to grips with an entire codebase? I watch it in the debugger. I find little bugs and then try to fix them, and mostly do it by watching them in the debugger and gradually getting an understanding of how the code works using my process of binary chopping. I have to do a lot of reading and watching code to choose where my slicing-in-half experiment is going to be. The last time I did it was SmartAssembly. The old code was a complete mess, but at least it did things top to bottom. There wasn’t too much of some of the big abstractions where flow of control goes all over the place, into a base class and back again. Code’s really hard to understand when that happens. So I like to choose a little bug and try to fix it, and choose a bigger bug and try to fix it. Definitely learn by doing. I want to always have an aim so that I get a little achievement after every few hours of debugging. Once I’ve learnt the codebase I might be able to fix all the bugs in an hour, but I’d rather be using them as an aim while I’m learning the codebase. If I was a maintainer of a codebase, what should I do to make it as easy as possible for you to understand? Keep distinct concepts in different places. And name your stuff so that it’s obvious which concepts live there. You shouldn’t have some variable that gets set miles up the top of somewhere, and then is read miles down to choose some later behaviour. I’m talking from a very much SmartAssembly point of view because the old SmartAssembly codebase had tons and tons of these things, where it would read some property of the code and then deal with it later. Just thousands of variables in scope. Loads of things to think about. If you can keep concepts separate, then it aids me in my process of fixing bugs one at a time, because each bug is going to more or less be understandable in the one place where it is. And what about tests? Do you think they help at all? I’ve never had the opportunity to learn a codebase which has had tests, I don’t know what it’s like! What about when you’re actually developing? How useful do you find tests in finding bugs or regressions? Finding regressions, absolutely. Running bits of code that would be quite hard to run otherwise, definitely. It doesn’t happen very often that a test finds a bug in the first place. I don’t really buy nebulous promises like tests being a good way to think about the spec of the code. My thinking goes something like “This code works at the moment, great, ship it! Ah, there’s a way that this code doesn’t work. Okay, write a test, demonstrate that it doesn’t work, fix it, use the test to demonstrate that it’s now fixed, and keep the test for future regressions.” The most valuable tests are for bugs that have actually happened at some point, because bugs that have actually happened at some point, despite the fact that you think you’ve fixed them, are way more likely to appear again than new bugs are. Does that mean that when you write your code the first time, there are no tests? Often. The chance of there being a bug in a new feature is relatively unaffected by whether I’ve written a test for that new feature because I’m not good enough at writing tests to think of bugs that I would have written into the code. So not writing regression tests for all of your code hasn’t affected you too badly? There are different kinds of features. Some of them just always work, and are just not flaky, they just continue working whatever you throw at them. Maybe because the type-checker is particularly effective around them. Writing tests for those features which just tend to always work is a waste of time. And because it’s a waste of time I’ll tend to wait until a feature has demonstrated its flakiness by having bugs in it before I start trying to test it. You can get a feel for whether it’s going to be flaky code as you’re writing it. I try to write it to make it not flaky, but there are some things that are just inherently flaky. And very occasionally, I’ll think “this is going to be flaky” as I’m writing, and then maybe do a test, but not most of the time. How do you think your programming style has changed over time? I’ve got clearer about what the right way of doing things is. I used to flip-flop a lot between different ideas. Five years ago I came up with some really good ideas and some really terrible ideas. All of them seemed great when I thought of them, but they were quite diverse ideas, whereas now I have a smaller set of reliable ideas that are actually good for structuring code. So my code is probably more similar to itself than it used to be back in the day, when I was trying stuff out. I’ve got more disciplined about encapsulation, I think. There are operational things like I use actors more now than I used to, and that forces me to use immutability more than I used to. The first code that I wrote in Red Gate was the memory profiler UI, and that was an actor, I just didn’t know the name of it at the time. I don’t really use object-orientation. By object-orientation, I mean having n objects of the same type which are mutable. I want a constant number of objects that are mutable, and they should be different types. I stick stuff in dictionaries and then have one thing that owns the dictionary and puts stuff in and out of it. That’s definitely a pattern that I’ve seen recently. I think maybe I’m doing functional programming. Possibly. It’s plausible. If you had to summarise the essence of programming in a pithy sentence, how would you do it? Programming is the form of art that, without losing any of the beauty of architecture or fine art, allows you to produce things that people love and you make money from. So you think it’s an art rather than a science? It’s a little bit of engineering, a smidgeon of maths, but it’s not science. Like architecture, programming is on that boundary between art and engineering. If you want to do it really nicely, it’s mostly art. You can get away with doing architecture and programming entirely by having a good engineering mind, but you’re not going to produce anything nice. You’re not going to have joy doing it if you’re an engineering mind. Architects who are just engineering minds are not going to enjoy their job. I suppose engineering is the foundation on which you build the art. Exactly. How do you think programming is going to change over the next ten years? There will be an unfortunate shift towards dynamically-typed languages, because of JavaScript. JavaScript has an unfair advantage. JavaScript’s unfair advantage will cause more people to be exposed to dynamically-typed languages, which means other dynamically-typed languages crop up and the best features go into dynamically-typed languages. Then people conflate the good features with the fact that it’s dynamically-typed, and more investment goes into dynamically-typed languages. They end up better, so people use them. What about the idea of compiling other languages, possibly statically-typed, to JavaScript? It’s a reasonable idea. I would like to do it, but I don’t think enough people in the world are going to do it to make it pick up. The hordes of beginners are the lifeblood of a language community. They are what makes there be good tools and what makes there be vibrant community websites. And any particular thing which is the same as JavaScript only with extra stuff added to it, although it might be technically great, is not going to have the hordes of beginners. JavaScript is always to be quickest and easiest way for a beginner to start programming in the browser. And dynamically-typed languages are great for beginners. Compilers are pretty scary and beginners don’t write big code. And having your errors come up in the same place, whether they’re statically checkable errors or not, is quite nice for a beginner. If someone asked me to teach them some programming, I’d teach them JavaScript. If dynamically-typed languages are great for beginners, when do you think the benefits of static typing start to kick in? The value of having a statically typed program is in the tools that rely on the static types to produce a smooth IDE experience rather than actually telling me my compile errors. And only once you’re experienced enough a programmer that having a really smooth IDE experience makes a blind bit of difference, does static typing make a blind bit of difference. So it’s not really about size of codebase. If I go and write up a tiny program, I’m still going to get value out of writing it in C# using ReSharper because I’m experienced with C# and ReSharper enough to be able to write code five times faster if I have that help. Any other visions of the future? Nobody’s going to use actors. Because everyone’s going to be running on single-core VMs connected over network-ready protocols like JSON over HTTP. So, parallelism within one operating system is going to die. But until then, you should use actors. More Red Gater Coder interviews

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  • value types in the vm

    - by john.rose
    value types in the vm p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times} p.p2 {margin: 0.0px 0.0px 14.0px 0.0px; font: 14.0px Times} p.p3 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times} p.p4 {margin: 0.0px 0.0px 15.0px 0.0px; font: 14.0px Times} p.p5 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Courier} p.p6 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Courier; min-height: 17.0px} p.p7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times; min-height: 18.0px} p.p8 {margin: 0.0px 0.0px 0.0px 36.0px; text-indent: -36.0px; font: 14.0px Times; min-height: 18.0px} p.p9 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times; min-height: 18.0px} p.p10 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times; color: #000000} li.li1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times} li.li7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times; min-height: 18.0px} span.s1 {font: 14.0px Courier} span.s2 {color: #000000} span.s3 {font: 14.0px Courier; color: #000000} ol.ol1 {list-style-type: decimal} Or, enduring values for a changing world. Introduction A value type is a data type which, generally speaking, is designed for being passed by value in and out of methods, and stored by value in data structures. The only value types which the Java language directly supports are the eight primitive types. Java indirectly and approximately supports value types, if they are implemented in terms of classes. For example, both Integer and String may be viewed as value types, especially if their usage is restricted to avoid operations appropriate to Object. In this note, we propose a definition of value types in terms of a design pattern for Java classes, accompanied by a set of usage restrictions. We also sketch the relation of such value types to tuple types (which are a JVM-level notion), and point out JVM optimizations that can apply to value types. This note is a thought experiment to extend the JVM’s performance model in support of value types. The demonstration has two phases.  Initially the extension can simply use design patterns, within the current bytecode architecture, and in today’s Java language. But if the performance model is to be realized in practice, it will probably require new JVM bytecode features, changes to the Java language, or both.  We will look at a few possibilities for these new features. An Axiom of Value In the context of the JVM, a value type is a data type equipped with construction, assignment, and equality operations, and a set of typed components, such that, whenever two variables of the value type produce equal corresponding values for their components, the values of the two variables cannot be distinguished by any JVM operation. Here are some corollaries: A value type is immutable, since otherwise a copy could be constructed and the original could be modified in one of its components, allowing the copies to be distinguished. Changing the component of a value type requires construction of a new value. The equals and hashCode operations are strictly component-wise. If a value type is represented by a JVM reference, that reference cannot be successfully synchronized on, and cannot be usefully compared for reference equality. A value type can be viewed in terms of what it doesn’t do. We can say that a value type omits all value-unsafe operations, which could violate the constraints on value types.  These operations, which are ordinarily allowed for Java object types, are pointer equality comparison (the acmp instruction), synchronization (the monitor instructions), all the wait and notify methods of class Object, and non-trivial finalize methods. The clone method is also value-unsafe, although for value types it could be treated as the identity function. Finally, and most importantly, any side effect on an object (however visible) also counts as an value-unsafe operation. A value type may have methods, but such methods must not change the components of the value. It is reasonable and useful to define methods like toString, equals, and hashCode on value types, and also methods which are specifically valuable to users of the value type. Representations of Value Value types have two natural representations in the JVM, unboxed and boxed. An unboxed value consists of the components, as simple variables. For example, the complex number x=(1+2i), in rectangular coordinate form, may be represented in unboxed form by the following pair of variables: /*Complex x = Complex.valueOf(1.0, 2.0):*/ double x_re = 1.0, x_im = 2.0; These variables might be locals, parameters, or fields. Their association as components of a single value is not defined to the JVM. Here is a sample computation which computes the norm of the difference between two complex numbers: double distance(/*Complex x:*/ double x_re, double x_im,         /*Complex y:*/ double y_re, double y_im) {     /*Complex z = x.minus(y):*/     double z_re = x_re - y_re, z_im = x_im - y_im;     /*return z.abs():*/     return Math.sqrt(z_re*z_re + z_im*z_im); } A boxed representation groups component values under a single object reference. The reference is to a ‘wrapper class’ that carries the component values in its fields. (A primitive type can naturally be equated with a trivial value type with just one component of that type. In that view, the wrapper class Integer can serve as a boxed representation of value type int.) The unboxed representation of complex numbers is practical for many uses, but it fails to cover several major use cases: return values, array elements, and generic APIs. The two components of a complex number cannot be directly returned from a Java function, since Java does not support multiple return values. The same story applies to array elements: Java has no ’array of structs’ feature. (Double-length arrays are a possible workaround for complex numbers, but not for value types with heterogeneous components.) By generic APIs I mean both those which use generic types, like Arrays.asList and those which have special case support for primitive types, like String.valueOf and PrintStream.println. Those APIs do not support unboxed values, and offer some problems to boxed values. Any ’real’ JVM type should have a story for returns, arrays, and API interoperability. The basic problem here is that value types fall between primitive types and object types. Value types are clearly more complex than primitive types, and object types are slightly too complicated. Objects are a little bit dangerous to use as value carriers, since object references can be compared for pointer equality, and can be synchronized on. Also, as many Java programmers have observed, there is often a performance cost to using wrapper objects, even on modern JVMs. Even so, wrapper classes are a good starting point for talking about value types. If there were a set of structural rules and restrictions which would prevent value-unsafe operations on value types, wrapper classes would provide a good notation for defining value types. This note attempts to define such rules and restrictions. Let’s Start Coding Now it is time to look at some real code. Here is a definition, written in Java, of a complex number value type. @ValueSafe public final class Complex implements java.io.Serializable {     // immutable component structure:     public final double re, im;     private Complex(double re, double im) {         this.re = re; this.im = im;     }     // interoperability methods:     public String toString() { return "Complex("+re+","+im+")"; }     public List<Double> asList() { return Arrays.asList(re, im); }     public boolean equals(Complex c) {         return re == c.re && im == c.im;     }     public boolean equals(@ValueSafe Object x) {         return x instanceof Complex && equals((Complex) x);     }     public int hashCode() {         return 31*Double.valueOf(re).hashCode()                 + Double.valueOf(im).hashCode();     }     // factory methods:     public static Complex valueOf(double re, double im) {         return new Complex(re, im);     }     public Complex changeRe(double re2) { return valueOf(re2, im); }     public Complex changeIm(double im2) { return valueOf(re, im2); }     public static Complex cast(@ValueSafe Object x) {         return x == null ? ZERO : (Complex) x;     }     // utility methods and constants:     public Complex plus(Complex c)  { return new Complex(re+c.re, im+c.im); }     public Complex minus(Complex c) { return new Complex(re-c.re, im-c.im); }     public double abs() { return Math.sqrt(re*re + im*im); }     public static final Complex PI = valueOf(Math.PI, 0.0);     public static final Complex ZERO = valueOf(0.0, 0.0); } This is not a minimal definition, because it includes some utility methods and other optional parts.  The essential elements are as follows: The class is marked as a value type with an annotation. The class is final, because it does not make sense to create subclasses of value types. The fields of the class are all non-private and final.  (I.e., the type is immutable and structurally transparent.) From the supertype Object, all public non-final methods are overridden. The constructor is private. Beyond these bare essentials, we can observe the following features in this example, which are likely to be typical of all value types: One or more factory methods are responsible for value creation, including a component-wise valueOf method. There are utility methods for complex arithmetic and instance creation, such as plus and changeIm. There are static utility constants, such as PI. The type is serializable, using the default mechanisms. There are methods for converting to and from dynamically typed references, such as asList and cast. The Rules In order to use value types properly, the programmer must avoid value-unsafe operations.  A helpful Java compiler should issue errors (or at least warnings) for code which provably applies value-unsafe operations, and should issue warnings for code which might be correct but does not provably avoid value-unsafe operations.  No such compilers exist today, but to simplify our account here, we will pretend that they do exist. A value-safe type is any class, interface, or type parameter marked with the @ValueSafe annotation, or any subtype of a value-safe type.  If a value-safe class is marked final, it is in fact a value type.  All other value-safe classes must be abstract.  The non-static fields of a value class must be non-public and final, and all its constructors must be private. Under the above rules, a standard interface could be helpful to define value types like Complex.  Here is an example: @ValueSafe public interface ValueType extends java.io.Serializable {     // All methods listed here must get redefined.     // Definitions must be value-safe, which means     // they may depend on component values only.     List<? extends Object> asList();     int hashCode();     boolean equals(@ValueSafe Object c);     String toString(); } //@ValueSafe inherited from supertype: public final class Complex implements ValueType { … The main advantage of such a conventional interface is that (unlike an annotation) it is reified in the runtime type system.  It could appear as an element type or parameter bound, for facilities which are designed to work on value types only.  More broadly, it might assist the JVM to perform dynamic enforcement of the rules for value types. Besides types, the annotation @ValueSafe can mark fields, parameters, local variables, and methods.  (This is redundant when the type is also value-safe, but may be useful when the type is Object or another supertype of a value type.)  Working forward from these annotations, an expression E is defined as value-safe if it satisfies one or more of the following: The type of E is a value-safe type. E names a field, parameter, or local variable whose declaration is marked @ValueSafe. E is a call to a method whose declaration is marked @ValueSafe. E is an assignment to a value-safe variable, field reference, or array reference. E is a cast to a value-safe type from a value-safe expression. E is a conditional expression E0 ? E1 : E2, and both E1 and E2 are value-safe. Assignments to value-safe expressions and initializations of value-safe names must take their values from value-safe expressions. A value-safe expression may not be the subject of a value-unsafe operation.  In particular, it cannot be synchronized on, nor can it be compared with the “==” operator, not even with a null or with another value-safe type. In a program where all of these rules are followed, no value-type value will be subject to a value-unsafe operation.  Thus, the prime axiom of value types will be satisfied, that no two value type will be distinguishable as long as their component values are equal. More Code To illustrate these rules, here are some usage examples for Complex: Complex pi = Complex.valueOf(Math.PI, 0); Complex zero = pi.changeRe(0);  //zero = pi; zero.re = 0; ValueType vtype = pi; @SuppressWarnings("value-unsafe")   Object obj = pi; @ValueSafe Object obj2 = pi; obj2 = new Object();  // ok List<Complex> clist = new ArrayList<Complex>(); clist.add(pi);  // (ok assuming List.add param is @ValueSafe) List<ValueType> vlist = new ArrayList<ValueType>(); vlist.add(pi);  // (ok) List<Object> olist = new ArrayList<Object>(); olist.add(pi);  // warning: "value-unsafe" boolean z = pi.equals(zero); boolean z1 = (pi == zero);  // error: reference comparison on value type boolean z2 = (pi == null);  // error: reference comparison on value type boolean z3 = (pi == obj2);  // error: reference comparison on value type synchronized (pi) { }  // error: synch of value, unpredictable result synchronized (obj2) { }  // unpredictable result Complex qq = pi; qq = null;  // possible NPE; warning: “null-unsafe" qq = (Complex) obj;  // warning: “null-unsafe" qq = Complex.cast(obj);  // OK @SuppressWarnings("null-unsafe")   Complex empty = null;  // possible NPE qq = empty;  // possible NPE (null pollution) The Payoffs It follows from this that either the JVM or the java compiler can replace boxed value-type values with unboxed ones, without affecting normal computations.  Fields and variables of value types can be split into their unboxed components.  Non-static methods on value types can be transformed into static methods which take the components as value parameters. Some common questions arise around this point in any discussion of value types. Why burden the programmer with all these extra rules?  Why not detect programs automagically and perform unboxing transparently?  The answer is that it is easy to break the rules accidently unless they are agreed to by the programmer and enforced.  Automatic unboxing optimizations are tantalizing but (so far) unreachable ideal.  In the current state of the art, it is possible exhibit benchmarks in which automatic unboxing provides the desired effects, but it is not possible to provide a JVM with a performance model that assures the programmer when unboxing will occur.  This is why I’m writing this note, to enlist help from, and provide assurances to, the programmer.  Basically, I’m shooting for a good set of user-supplied “pragmas” to frame the desired optimization. Again, the important thing is that the unboxing must be done reliably, or else programmers will have no reason to work with the extra complexity of the value-safety rules.  There must be a reasonably stable performance model, wherein using a value type has approximately the same performance characteristics as writing the unboxed components as separate Java variables. There are some rough corners to the present scheme.  Since Java fields and array elements are initialized to null, value-type computations which incorporate uninitialized variables can produce null pointer exceptions.  One workaround for this is to require such variables to be null-tested, and the result replaced with a suitable all-zero value of the value type.  That is what the “cast” method does above. Generically typed APIs like List<T> will continue to manipulate boxed values always, at least until we figure out how to do reification of generic type instances.  Use of such APIs will elicit warnings until their type parameters (and/or relevant members) are annotated or typed as value-safe.  Retrofitting List<T> is likely to expose flaws in the present scheme, which we will need to engineer around.  Here are a couple of first approaches: public interface java.util.List<@ValueSafe T> extends Collection<T> { … public interface java.util.List<T extends Object|ValueType> extends Collection<T> { … (The second approach would require disjunctive types, in which value-safety is “contagious” from the constituent types.) With more transformations, the return value types of methods can also be unboxed.  This may require significant bytecode-level transformations, and would work best in the presence of a bytecode representation for multiple value groups, which I have proposed elsewhere under the title “Tuples in the VM”. But for starters, the JVM can apply this transformation under the covers, to internally compiled methods.  This would give a way to express multiple return values and structured return values, which is a significant pain-point for Java programmers, especially those who work with low-level structure types favored by modern vector and graphics processors.  The lack of multiple return values has a strong distorting effect on many Java APIs. Even if the JVM fails to unbox a value, there is still potential benefit to the value type.  Clustered computing systems something have copy operations (serialization or something similar) which apply implicitly to command operands.  When copying JVM objects, it is extremely helpful to know when an object’s identity is important or not.  If an object reference is a copied operand, the system may have to create a proxy handle which points back to the original object, so that side effects are visible.  Proxies must be managed carefully, and this can be expensive.  On the other hand, value types are exactly those types which a JVM can “copy and forget” with no downside. Array types are crucial to bulk data interfaces.  (As data sizes and rates increase, bulk data becomes more important than scalar data, so arrays are definitely accompanying us into the future of computing.)  Value types are very helpful for adding structure to bulk data, so a successful value type mechanism will make it easier for us to express richer forms of bulk data. Unboxing arrays (i.e., arrays containing unboxed values) will provide better cache and memory density, and more direct data movement within clustered or heterogeneous computing systems.  They require the deepest transformations, relative to today’s JVM.  There is an impedance mismatch between value-type arrays and Java’s covariant array typing, so compromises will need to be struck with existing Java semantics.  It is probably worth the effort, since arrays of unboxed value types are inherently more memory-efficient than standard Java arrays, which rely on dependent pointer chains. It may be sufficient to extend the “value-safe” concept to array declarations, and allow low-level transformations to change value-safe array declarations from the standard boxed form into an unboxed tuple-based form.  Such value-safe arrays would not be convertible to Object[] arrays.  Certain connection points, such as Arrays.copyOf and System.arraycopy might need additional input/output combinations, to allow smooth conversion between arrays with boxed and unboxed elements. Alternatively, the correct solution may have to wait until we have enough reification of generic types, and enough operator overloading, to enable an overhaul of Java arrays. Implicit Method Definitions The example of class Complex above may be unattractively complex.  I believe most or all of the elements of the example class are required by the logic of value types. If this is true, a programmer who writes a value type will have to write lots of error-prone boilerplate code.  On the other hand, I think nearly all of the code (except for the domain-specific parts like plus and minus) can be implicitly generated. Java has a rule for implicitly defining a class’s constructor, if no it defines no constructors explicitly.  Likewise, there are rules for providing default access modifiers for interface members.  Because of the highly regular structure of value types, it might be reasonable to perform similar implicit transformations on value types.  Here’s an example of a “highly implicit” definition of a complex number type: public class Complex implements ValueType {  // implicitly final     public double re, im;  // implicitly public final     //implicit methods are defined elementwise from te fields:     //  toString, asList, equals(2), hashCode, valueOf, cast     //optionally, explicit methods (plus, abs, etc.) would go here } In other words, with the right defaults, a simple value type definition can be a one-liner.  The observant reader will have noticed the similarities (and suitable differences) between the explicit methods above and the corresponding methods for List<T>. Another way to abbreviate such a class would be to make an annotation the primary trigger of the functionality, and to add the interface(s) implicitly: public @ValueType class Complex { … // implicitly final, implements ValueType (But to me it seems better to communicate the “magic” via an interface, even if it is rooted in an annotation.) Implicitly Defined Value Types So far we have been working with nominal value types, which is to say that the sequence of typed components is associated with a name and additional methods that convey the intention of the programmer.  A simple ordered pair of floating point numbers can be variously interpreted as (to name a few possibilities) a rectangular or polar complex number or Cartesian point.  The name and the methods convey the intended meaning. But what if we need a truly simple ordered pair of floating point numbers, without any further conceptual baggage?  Perhaps we are writing a method (like “divideAndRemainder”) which naturally returns a pair of numbers instead of a single number.  Wrapping the pair of numbers in a nominal type (like “QuotientAndRemainder”) makes as little sense as wrapping a single return value in a nominal type (like “Quotient”).  What we need here are structural value types commonly known as tuples. For the present discussion, let us assign a conventional, JVM-friendly name to tuples, roughly as follows: public class java.lang.tuple.$DD extends java.lang.tuple.Tuple {      double $1, $2; } Here the component names are fixed and all the required methods are defined implicitly.  The supertype is an abstract class which has suitable shared declarations.  The name itself mentions a JVM-style method parameter descriptor, which may be “cracked” to determine the number and types of the component fields. The odd thing about such a tuple type (and structural types in general) is it must be instantiated lazily, in response to linkage requests from one or more classes that need it.  The JVM and/or its class loaders must be prepared to spin a tuple type on demand, given a simple name reference, $xyz, where the xyz is cracked into a series of component types.  (Specifics of naming and name mangling need some tasteful engineering.) Tuples also seem to demand, even more than nominal types, some support from the language.  (This is probably because notations for non-nominal types work best as combinations of punctuation and type names, rather than named constructors like Function3 or Tuple2.)  At a minimum, languages with tuples usually (I think) have some sort of simple bracket notation for creating tuples, and a corresponding pattern-matching syntax (or “destructuring bind”) for taking tuples apart, at least when they are parameter lists.  Designing such a syntax is no simple thing, because it ought to play well with nominal value types, and also with pre-existing Java features, such as method parameter lists, implicit conversions, generic types, and reflection.  That is a task for another day. Other Use Cases Besides complex numbers and simple tuples there are many use cases for value types.  Many tuple-like types have natural value-type representations. These include rational numbers, point locations and pixel colors, and various kinds of dates and addresses. Other types have a variable-length ‘tail’ of internal values. The most common example of this is String, which is (mathematically) a sequence of UTF-16 character values. Similarly, bit vectors, multiple-precision numbers, and polynomials are composed of sequences of values. Such types include, in their representation, a reference to a variable-sized data structure (often an array) which (somehow) represents the sequence of values. The value type may also include ’header’ information. Variable-sized values often have a length distribution which favors short lengths. In that case, the design of the value type can make the first few values in the sequence be direct ’header’ fields of the value type. In the common case where the header is enough to represent the whole value, the tail can be a shared null value, or even just a null reference. Note that the tail need not be an immutable object, as long as the header type encapsulates it well enough. This is the case with String, where the tail is a mutable (but never mutated) character array. Field types and their order must be a globally visible part of the API.  The structure of the value type must be transparent enough to have a globally consistent unboxed representation, so that all callers and callees agree about the type and order of components  that appear as parameters, return types, and array elements.  This is a trade-off between efficiency and encapsulation, which is forced on us when we remove an indirection enjoyed by boxed representations.  A JVM-only transformation would not care about such visibility, but a bytecode transformation would need to take care that (say) the components of complex numbers would not get swapped after a redefinition of Complex and a partial recompile.  Perhaps constant pool references to value types need to declare the field order as assumed by each API user. This brings up the delicate status of private fields in a value type.  It must always be possible to load, store, and copy value types as coordinated groups, and the JVM performs those movements by moving individual scalar values between locals and stack.  If a component field is not public, what is to prevent hostile code from plucking it out of the tuple using a rogue aload or astore instruction?  Nothing but the verifier, so we may need to give it more smarts, so that it treats value types as inseparable groups of stack slots or locals (something like long or double). My initial thought was to make the fields always public, which would make the security problem moot.  But public is not always the right answer; consider the case of String, where the underlying mutable character array must be encapsulated to prevent security holes.  I believe we can win back both sides of the tradeoff, by training the verifier never to split up the components in an unboxed value.  Just as the verifier encapsulates the two halves of a 64-bit primitive, it can encapsulate the the header and body of an unboxed String, so that no code other than that of class String itself can take apart the values. Similar to String, we could build an efficient multi-precision decimal type along these lines: public final class DecimalValue extends ValueType {     protected final long header;     protected private final BigInteger digits;     public DecimalValue valueOf(int value, int scale) {         assert(scale >= 0);         return new DecimalValue(((long)value << 32) + scale, null);     }     public DecimalValue valueOf(long value, int scale) {         if (value == (int) value)             return valueOf((int)value, scale);         return new DecimalValue(-scale, new BigInteger(value));     } } Values of this type would be passed between methods as two machine words. Small values (those with a significand which fits into 32 bits) would be represented without any heap data at all, unless the DecimalValue itself were boxed. (Note the tension between encapsulation and unboxing in this case.  It would be better if the header and digits fields were private, but depending on where the unboxing information must “leak”, it is probably safer to make a public revelation of the internal structure.) Note that, although an array of Complex can be faked with a double-length array of double, there is no easy way to fake an array of unboxed DecimalValues.  (Either an array of boxed values or a transposed pair of homogeneous arrays would be reasonable fallbacks, in a current JVM.)  Getting the full benefit of unboxing and arrays will require some new JVM magic. Although the JVM emphasizes portability, system dependent code will benefit from using machine-level types larger than 64 bits.  For example, the back end of a linear algebra package might benefit from value types like Float4 which map to stock vector types.  This is probably only worthwhile if the unboxing arrays can be packed with such values. More Daydreams A more finely-divided design for dynamic enforcement of value safety could feature separate marker interfaces for each invariant.  An empty marker interface Unsynchronizable could cause suitable exceptions for monitor instructions on objects in marked classes.  More radically, a Interchangeable marker interface could cause JVM primitives that are sensitive to object identity to raise exceptions; the strangest result would be that the acmp instruction would have to be specified as raising an exception. @ValueSafe public interface ValueType extends java.io.Serializable,         Unsynchronizable, Interchangeable { … public class Complex implements ValueType {     // inherits Serializable, Unsynchronizable, Interchangeable, @ValueSafe     … It seems possible that Integer and the other wrapper types could be retro-fitted as value-safe types.  This is a major change, since wrapper objects would be unsynchronizable and their references interchangeable.  It is likely that code which violates value-safety for wrapper types exists but is uncommon.  It is less plausible to retro-fit String, since the prominent operation String.intern is often used with value-unsafe code. We should also reconsider the distinction between boxed and unboxed values in code.  The design presented above obscures that distinction.  As another thought experiment, we could imagine making a first class distinction in the type system between boxed and unboxed representations.  Since only primitive types are named with a lower-case initial letter, we could define that the capitalized version of a value type name always refers to the boxed representation, while the initial lower-case variant always refers to boxed.  For example: complex pi = complex.valueOf(Math.PI, 0); Complex boxPi = pi;  // convert to boxed myList.add(boxPi); complex z = myList.get(0);  // unbox Such a convention could perhaps absorb the current difference between int and Integer, double and Double. It might also allow the programmer to express a helpful distinction among array types. As said above, array types are crucial to bulk data interfaces, but are limited in the JVM.  Extending arrays beyond the present limitations is worth thinking about; for example, the Maxine JVM implementation has a hybrid object/array type.  Something like this which can also accommodate value type components seems worthwhile.  On the other hand, does it make sense for value types to contain short arrays?  And why should random-access arrays be the end of our design process, when bulk data is often sequentially accessed, and it might make sense to have heterogeneous streams of data as the natural “jumbo” data structure.  These considerations must wait for another day and another note. More Work It seems to me that a good sequence for introducing such value types would be as follows: Add the value-safety restrictions to an experimental version of javac. Code some sample applications with value types, including Complex and DecimalValue. Create an experimental JVM which internally unboxes value types but does not require new bytecodes to do so.  Ensure the feasibility of the performance model for the sample applications. Add tuple-like bytecodes (with or without generic type reification) to a major revision of the JVM, and teach the Java compiler to switch in the new bytecodes without code changes. A staggered roll-out like this would decouple language changes from bytecode changes, which is always a convenient thing. A similar investigation should be applied (concurrently) to array types.  In this case, it seems to me that the starting point is in the JVM: Add an experimental unboxing array data structure to a production JVM, perhaps along the lines of Maxine hybrids.  No bytecode or language support is required at first; everything can be done with encapsulated unsafe operations and/or method handles. Create an experimental JVM which internally unboxes value types but does not require new bytecodes to do so.  Ensure the feasibility of the performance model for the sample applications. Add tuple-like bytecodes (with or without generic type reification) to a major revision of the JVM, and teach the Java compiler to switch in the new bytecodes without code changes. That’s enough musing me for now.  Back to work!

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  • "domain crashed" when creating new Xen instance

    - by user47650
    I have downloaded a Xen virtual machine image from the appscale project, and I am trying to start it up. However once I run the command; xm create -c -f xen.conf The instance immediately crashes and provides no console output. however it produces logs that I have posted below. but this is the error; [2011-03-01 12:34:03 xend.XendDomainInfo 3580] WARNING (XendDomainInfo:1178) Domain has crashed: name=appscale-1.4b id=10. I have managed to mount the root.img file locally and verify that it is actually an ext3 file system. I am running Xen 3.0.3 that is a stock RPM from the CentOS 5 repos; # rpm -qa | grep -i xen xen-libs-3.0.3-105.el5_5.5 xen-3.0.3-105.el5_5.5 xen-libs-3.0.3-105.el5_5.5 kernel-xen-2.6.18-194.32.1.el5 any suggestions on how to proceed with troubleshooting? (i am a newbie to Xen) so far I have enabled console logging, but the log file is empty. ==> domain-builder-ng.log <== xc_dom_allocate: cmdline=" ip=:1.2.3.4::::eth0:dhcp root=/dev/sda1 ro xencons=tty console=tty1 console=hvc0 debugger=y debug=y sync_console", features="" xc_dom_kernel_file: filename="/boot/vmlinuz-2.6.27-7-server" xc_dom_malloc_filemap : 2284 kB xc_dom_ramdisk_file: filename="/boot/initrd.img-2.6.27-7-server" xc_dom_malloc_filemap : 9005 kB xc_dom_boot_xen_init: ver 3.1, caps xen-3.0-x86_64 xen-3.0-x86_32p xc_dom_parse_image: called xc_dom_find_loader: trying ELF-generic loader ... failed xc_dom_find_loader: trying Linux bzImage loader ... xc_dom_malloc : 9875 kB xc_dom_do_gunzip: unzip ok, 0x234bb2 -> 0x9a4de0 OK elf_parse_binary: phdr: paddr=0x200000 memsz=0x447000 elf_parse_binary: phdr: paddr=0x647000 memsz=0xab888 elf_parse_binary: phdr: paddr=0x6f3000 memsz=0x908 elf_parse_binary: phdr: paddr=0x6f4000 memsz=0x1c2f9c elf_parse_binary: memory: 0x200000 -> 0x8b6f9c elf_xen_parse_note: GUEST_OS = "linux" elf_xen_parse_note: GUEST_VERSION = "2.6" elf_xen_parse_note: XEN_VERSION = "xen-3.0" elf_xen_parse_note: VIRT_BASE = 0xffffffff80000000 elf_xen_parse_note: ENTRY = 0xffffffff8071e200 elf_xen_parse_note: HYPERCALL_PAGE = 0xffffffff80209000 elf_xen_parse_note: FEATURES = "!writable_page_tables|pae_pgdir_above_4gb" elf_xen_parse_note: PAE_MODE = "yes" elf_xen_parse_note: LOADER = "generic" elf_xen_parse_note: unknown xen elf note (0xd) elf_xen_parse_note: SUSPEND_CANCEL = 0x1 elf_xen_parse_note: HV_START_LOW = 0xffff800000000000 elf_xen_parse_note: PADDR_OFFSET = 0x0 elf_xen_addr_calc_check: addresses: virt_base = 0xffffffff80000000 elf_paddr_offset = 0x0 virt_offset = 0xffffffff80000000 virt_kstart = 0xffffffff80200000 virt_kend = 0xffffffff808b6f9c virt_entry = 0xffffffff8071e200 xc_dom_parse_elf_kernel: xen-3.0-x86_64: 0xffffffff80200000 -> 0xffffffff808b6f9c xc_dom_mem_init: mem 1024 MB, pages 0x40000 pages, 4k each xc_dom_mem_init: 0x40000 pages xc_dom_boot_mem_init: called x86_compat: guest xen-3.0-x86_64, address size 64 xc_dom_malloc : 2048 kB ==> xend.log <== [2011-03-01 12:34:01 xend.XendDomainInfo 3580] INFO (XendDomainInfo:2330) Dev 2049 still active, looping... [2011-03-01 12:34:01 xend.XendDomainInfo 3580] INFO (XendDomainInfo:2330) Dev 2049 still active, looping... [2011-03-01 12:34:01 xend.XendDomainInfo 3580] INFO (XendDomainInfo:2330) Dev 2049 still active, looping... [2011-03-01 12:34:01 xend.XendDomainInfo 3580] INFO (XendDomainInfo:2330) Dev 2049 still active, looping... [2011-03-01 12:34:01 xend.XendDomainInfo 3580] INFO (XendDomainInfo:957) Dev 0 still active, looping... [2011-03-01 12:34:01 xend.XendDomainInfo 3580] INFO (XendDomainInfo:957) Dev 0 still active, looping... [2011-03-01 12:34:01 xend.XendDomainInfo 3580] INFO (XendDomainInfo:957) Dev 0 still active, looping... [2011-03-01 12:34:02 xend.XendDomainInfo 3580] INFO (XendDomainInfo:957) Dev 0 still active, looping... [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:2114) UUID Created: True [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:2115) Devices to release: [], domid = 9 [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:2127) Releasing PVFB backend devices ... [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:207) XendDomainInfo.create(['domain', ['domid', 9], ['uuid', 'd5f22dd4-8dc2-f51f-84e9-eea7d71ea1d0'], ['vcpus', 1], ['vcpu_avail', 1], ['cpu_cap', 0], ['cpu_weight', 256], ['memory', 1024], ['shadow_memory', 0], ['maxmem', 1024], ['features', ''], ['name', 'appscale-1.4b'], ['on_poweroff', 'destroy'], ['on_reboot', 'restart'], ['on_crash', 'restart'], ['image', ['linux', ['kernel', '/boot/vmlinuz-2.6.27-7-server'], ['ramdisk', '/boot/initrd.img-2.6.27-7-server'], ['ip', ':1.2.3.4::::eth0:dhcp'], ['root', '/dev/sda1 ro'], ['args', 'xencons=tty console=tty1 console=hvc0 debugger=y debug=y sync_console']]], ['cpus', []], ['device', ['vif', ['backend', 0], ['script', 'vif-bridge'], ['mac', '00:16:3B:72:10:E4']]], ['device', ['vbd', ['backend', 0], ['dev', 'sda1:disk'], ['uname', 'file:/local/xen/domains/appscale1.4/root.img'], ['mode', 'w']]], ['state', '----c-'], ['shutdown_reason', 'crash'], ['cpu_time', 0.000339131], ['online_vcpus', 1], ['up_time', '0.952092885971'], ['start_time', '1299011639.92'], ['store_mfn', 1169289], ['console_mfn', 1169288]]) [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:329) parseConfig: config is ['domain', ['domid', 9], ['uuid', 'd5f22dd4-8dc2-f51f-84e9-eea7d71ea1d0'], ['vcpus', 1], ['vcpu_avail', 1], ['cpu_cap', 0], ['cpu_weight', 256], ['memory', 1024], ['shadow_memory', 0], ['maxmem', 1024], ['features', ''], ['name', 'appscale-1.4b'], ['on_poweroff', 'destroy'], ['on_reboot', 'restart'], ['on_crash', 'restart'], ['image', ['linux', ['kernel', '/boot/vmlinuz-2.6.27-7-server'], ['ramdisk', '/boot/initrd.img-2.6.27-7-server'], ['ip', ':1.2.3.4::::eth0:dhcp'], ['root', '/dev/sda1 ro'], ['args', 'xencons=tty console=tty1 console=hvc0 debugger=y debug=y sync_console']]], ['cpus', []], ['device', ['vif', ['backend', 0], ['script', 'vif-bridge'], ['mac', '00:16:3B:72:10:E4']]], ['device', ['vbd', ['backend', 0], ['dev', 'sda1:disk'], ['uname', 'file:/local/xen/domains/appscale1.4/root.img'], ['mode', 'w']]], ['state', '----c-'], ['shutdown_reason', 'crash'], ['cpu_time', 0.000339131], ['online_vcpus', 1], ['up_time', '0.952092885971'], ['start_time', '1299011639.92'], ['store_mfn', 1169289], ['console_mfn', 1169288]] [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:446) parseConfig: result is {'features': '', 'image': ['linux', ['kernel', '/boot/vmlinuz-2.6.27-7-server'], ['ramdisk', '/boot/initrd.img-2.6.27-7-server'], ['ip', ':1.2.3.4::::eth0:dhcp'], ['root', '/dev/sda1 ro'], ['args', 'xencons=tty console=tty1 console=hvc0 debugger=y debug=y sync_console']], 'cpus': [], 'vcpu_avail': 1, 'backend': [], 'uuid': 'd5f22dd4-8dc2-f51f-84e9-eea7d71ea1d0', 'on_reboot': 'restart', 'cpu_weight': 256.0, 'memory': 1024, 'cpu_cap': 0, 'localtime': None, 'timer_mode': None, 'start_time': 1299011639.9200001, 'on_poweroff': 'destroy', 'on_crash': 'restart', 'device': [('vif', ['vif', ['backend', 0], ['script', 'vif-bridge'], ['mac', '00:16:3B:72:10:E4']]), ('vbd', ['vbd', ['backend', 0], ['dev', 'sda1:disk'], ['uname', 'file:/local/xen/domains/appscale1.4/root.img'], ['mode', 'w']])], 'bootloader': None, 'maxmem': 1024, 'shadow_memory': 0, 'name': 'appscale-1.4b', 'bootloader_args': None, 'vcpus': 1, 'cpu': None} [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:1784) XendDomainInfo.construct: None [2011-03-01 12:34:02 xend 3580] DEBUG (balloon:145) Balloon: 3034420 KiB free; need 4096; done. [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:1953) XendDomainInfo.initDomain: 10 256.0 [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:1994) _initDomain:shadow_memory=0x0, maxmem=0x400, memory=0x400. [2011-03-01 12:34:02 xend 3580] DEBUG (balloon:145) Balloon: 3034412 KiB free; need 1048576; done. [2011-03-01 12:34:02 xend 3580] INFO (image:139) buildDomain os=linux dom=10 vcpus=1 [2011-03-01 12:34:02 xend 3580] DEBUG (image:208) domid = 10 [2011-03-01 12:34:02 xend 3580] DEBUG (image:209) memsize = 1024 [2011-03-01 12:34:02 xend 3580] DEBUG (image:210) image = /boot/vmlinuz-2.6.27-7-server [2011-03-01 12:34:02 xend 3580] DEBUG (image:211) store_evtchn = 1 [2011-03-01 12:34:02 xend 3580] DEBUG (image:212) console_evtchn = 2 [2011-03-01 12:34:02 xend 3580] DEBUG (image:213) cmdline = ip=:1.2.3.4::::eth0:dhcp root=/dev/sda1 ro xencons=tty console=tty1 console=hvc0 debugger=y debug=y sync_console [2011-03-01 12:34:02 xend 3580] DEBUG (image:214) ramdisk = /boot/initrd.img-2.6.27-7-server [2011-03-01 12:34:02 xend 3580] DEBUG (image:215) vcpus = 1 [2011-03-01 12:34:02 xend 3580] DEBUG (image:216) features = ==> domain-builder-ng.log <== xc_dom_build_image: called xc_dom_alloc_segment: kernel : 0xffffffff80200000 -> 0xffffffff808b7000 (pfn 0x200 + 0x6b7 pages) xc_dom_pfn_to_ptr: domU mapping: pfn 0x200+0x6b7 at 0x2aaaab5f6000 elf_load_binary: phdr 0 at 0x0x2aaaab5f6000 -> 0x0x2aaaaba3d000 elf_load_binary: phdr 1 at 0x0x2aaaaba3d000 -> 0x0x2aaaabae8888 elf_load_binary: phdr 2 at 0x0x2aaaabae9000 -> 0x0x2aaaabae9908 elf_load_binary: phdr 3 at 0x0x2aaaabaea000 -> 0x0x2aaaabb9a004 xc_dom_alloc_segment: ramdisk : 0xffffffff808b7000 -> 0xffffffff82382000 (pfn 0x8b7 + 0x1acb pages) xc_dom_malloc : 160 kB xc_dom_pfn_to_ptr: domU mapping: pfn 0x8b7+0x1acb at 0x2aaab0000000 xc_dom_do_gunzip: unzip ok, 0x8cb5e7 -> 0x1aca210 xc_dom_alloc_segment: phys2mach : 0xffffffff82382000 -> 0xffffffff82582000 (pfn 0x2382 + 0x200 pages) xc_dom_pfn_to_ptr: domU mapping: pfn 0x2382+0x200 at 0x2aaab1acb000 xc_dom_alloc_page : start info : 0xffffffff82582000 (pfn 0x2582) xc_dom_alloc_page : xenstore : 0xffffffff82583000 (pfn 0x2583) xc_dom_alloc_page : console : 0xffffffff82584000 (pfn 0x2584) nr_page_tables: 0x0000ffffffffffff/48: 0xffff000000000000 -> 0xffffffffffffffff, 1 table(s) nr_page_tables: 0x0000007fffffffff/39: 0xffffff8000000000 -> 0xffffffffffffffff, 1 table(s) nr_page_tables: 0x000000003fffffff/30: 0xffffffff80000000 -> 0xffffffffbfffffff, 1 table(s) nr_page_tables: 0x00000000001fffff/21: 0xffffffff80000000 -> 0xffffffff827fffff, 20 table(s) xc_dom_alloc_segment: page tables : 0xffffffff82585000 -> 0xffffffff8259c000 (pfn 0x2585 + 0x17 pages) xc_dom_pfn_to_ptr: domU mapping: pfn 0x2585+0x17 at 0x2aaab1ccb000 xc_dom_alloc_page : boot stack : 0xffffffff8259c000 (pfn 0x259c) xc_dom_build_image : virt_alloc_end : 0xffffffff8259d000 xc_dom_build_image : virt_pgtab_end : 0xffffffff82800000 xc_dom_boot_image: called arch_setup_bootearly: doing nothing xc_dom_compat_check: supported guest type: xen-3.0-x86_64 <= matches xc_dom_compat_check: supported guest type: xen-3.0-x86_32p xc_dom_update_guest_p2m: dst 64bit, pages 0x40000 clear_page: pfn 0x2584, mfn 0x11d788 clear_page: pfn 0x2583, mfn 0x11d789 xc_dom_pfn_to_ptr: domU mapping: pfn 0x2582+0x1 at 0x2aaab1ce2000 start_info_x86_64: called setup_hypercall_page: vaddr=0xffffffff80209000 pfn=0x209 domain builder memory footprint allocated malloc : 12139 kB anon mmap : 0 bytes mapped file mmap : 11289 kB domU mmap : 35 MB arch_setup_bootlate: shared_info: pfn 0x0, mfn 0xd6fe1 shared_info_x86_64: called vcpu_x86_64: called vcpu_x86_64: cr3: pfn 0x2585 mfn 0x11d787 launch_vm: called, ctxt=0x97b21f8 xc_dom_release: called ==> xend.log <== [2011-03-01 12:34:02 xend 3580] DEBUG (DevController:114) DevController: writing {'mac': '00:16:3B:72:10:E4', 'handle': '0', 'protocol': 'x86_64-abi', 'backend-id': '0', 'state': '1', 'backend': '/local/domain/0/backend/vif/10/0'} to /local/domain/10/device/vif/0. [2011-03-01 12:34:02 xend 3580] DEBUG (DevController:116) DevController: writing {'domain': 'appscale-1.4b', 'handle': '0', 'script': '/etc/xen/scripts/vif-bridge', 'state': '1', 'frontend': '/local/domain/10/device/vif/0', 'mac': '00:16:3B:72:10:E4', 'online': '1', 'frontend-id': '10'} to /local/domain/0/backend/vif/10/0. [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:634) Checking for duplicate for uname: /local/xen/domains/appscale1.4/root.img [file:/local/xen/domains/appscale1.4/root.img], dev: sda1:disk, mode: w [2011-03-01 12:34:02 xend 3580] DEBUG (blkif:27) exception looking up device number for sda1:disk: [Errno 2] No such file or directory: '/dev/sda1:disk' [2011-03-01 12:34:02 xend 3580] DEBUG (blkif:27) exception looking up device number for sda1: [Errno 2] No such file or directory: '/dev/sda1' [2011-03-01 12:34:02 xend 3580] DEBUG (DevController:114) DevController: writing {'virtual-device': '2049', 'device-type': 'disk', 'protocol': 'x86_64-abi', 'backend-id': '0', 'state': '1', 'backend': '/local/domain/0/backend/vbd/10/2049'} to /local/domain/10/device/vbd/2049. [2011-03-01 12:34:02 xend 3580] DEBUG (DevController:116) DevController: writing {'domain': 'appscale-1.4b', 'frontend': '/local/domain/10/device/vbd/2049', 'format': 'raw', 'dev': 'sda1', 'state': '1', 'params': '/local/xen/domains/appscale1.4/root.img', 'mode': 'w', 'online': '1', 'frontend-id': '10', 'type': 'file'} to /local/domain/0/backend/vbd/10/2049. [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:993) Storing VM details: {'shadow_memory': '0', 'uuid': 'd5f22dd4-8dc2-f51f-84e9-eea7d71ea1d0', 'on_reboot': 'restart', 'start_time': '1299011642.74', 'on_poweroff': 'destroy', 'name': 'appscale-1.4b', 'xend/restart_count': '0', 'vcpus': '1', 'vcpu_avail': '1', 'memory': '1024', 'on_crash': 'restart', 'image': "(linux (kernel /boot/vmlinuz-2.6.27-7-server) (ramdisk /boot/initrd.img-2.6.27-7-server) (ip :1.2.3.4::::eth0:dhcp) (root '/dev/sda1 ro') (args 'xencons=tty console=tty1 console=hvc0 debugger=y debug=y sync_console'))", 'maxmem': '1024'} [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:1028) Storing domain details: {'console/ring-ref': '1169288', 'console/port': '2', 'name': 'appscale-1.4b', 'console/limit': '1048576', 'vm': '/vm/d5f22dd4-8dc2-f51f-84e9-eea7d71ea1d0', 'domid': '10', 'cpu/0/availability': 'online', 'memory/target': '1048576', 'store/ring-ref': '1169289', 'store/port': '1'} [2011-03-01 12:34:02 xend 3580] DEBUG (DevController:158) Waiting for devices vif. [2011-03-01 12:34:02 xend 3580] DEBUG (DevController:164) Waiting for 0. [2011-03-01 12:34:02 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:1250) XendDomainInfo.handleShutdownWatch [2011-03-01 12:34:02 xend 3580] DEBUG (DevController:509) hotplugStatusCallback /local/domain/0/backend/vif/10/0/hotplug-status. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:509) hotplugStatusCallback /local/domain/0/backend/vif/10/0/hotplug-status. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:523) hotplugStatusCallback 1. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:158) Waiting for devices usb. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:158) Waiting for devices vbd. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:164) Waiting for 2049. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:509) hotplugStatusCallback /local/domain/0/backend/vbd/10/2049/hotplug-status. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:509) hotplugStatusCallback /local/domain/0/backend/vbd/10/2049/hotplug-status. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:523) hotplugStatusCallback 1. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:158) Waiting for devices irq. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:158) Waiting for devices vkbd. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:158) Waiting for devices vfb. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:158) Waiting for devices pci. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:158) Waiting for devices ioports. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:158) Waiting for devices tap. [2011-03-01 12:34:03 xend 3580] DEBUG (DevController:158) Waiting for devices vtpm. [2011-03-01 12:34:03 xend.XendDomainInfo 3580] WARNING (XendDomainInfo:1178) Domain has crashed: name=appscale-1.4b id=10. [2011-03-01 12:34:03 xend.XendDomainInfo 3580] ERROR (XendDomainInfo:2654) VM appscale-1.4b restarting too fast (2.275545 seconds since the last restart). Refusing to restart to avoid loops. [2011-03-01 12:34:03 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:2189) XendDomainInfo.destroy: domid=10 ==> xen-hotplug.log <== Nothing to flush. ==> xend.log <== [2011-03-01 12:34:03 xend.XendDomainInfo 3580] INFO (XendDomainInfo:2330) Dev 2049 still active, looping... [2011-03-01 12:34:03 xend.XendDomainInfo 3580] INFO (XendDomainInfo:2330) Dev 2049 still active, looping... [2011-03-01 12:34:03 xend.XendDomainInfo 3580] INFO (XendDomainInfo:2330) Dev 2049 still active, looping... [2011-03-01 12:34:03 xend.XendDomainInfo 3580] INFO (XendDomainInfo:2330) Dev 2049 still active, looping... [2011-03-01 12:34:03 xend.XendDomainInfo 3580] INFO (XendDomainInfo:2330) Dev 2049 still active, looping... [2011-03-01 12:34:03 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:2114) UUID Created: True [2011-03-01 12:34:03 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:2115) Devices to release: [], domid = 10 [2011-03-01 12:34:03 xend.XendDomainInfo 3580] DEBUG (XendDomainInfo:2127) Releasing PVFB backend devices ... And this is the xen.conf file that I am using; # cat xen.conf # Configuration file for the Xen instance AppScale, created # bn VMBuilder kernel = '/boot/vmlinuz-2.6.27-7-server' ramdisk = '/boot/initrd.img-2.6.27-7-server' memory = 1024 vcpus = 1 root = '/dev/sda1 ro' disk = [ 'file:/local/xen/domains/appscale1.4/root.img,sda1,w', ] name = 'appscale-1.4b' dhcp = 'dhcp' vif = [ 'mac=00:16:3B:72:10:E4' ] on_poweroff = 'destroy' on_reboot = 'restart' on_crash = 'restart' extra = 'xencons=tty console=tty1 console=hvc0 debugger=y debug=y sync_console'

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  • You Might Be a DBA

    - by BuckWoody
    With all apologies to Jeff Foxworthy, I was up late Friday night on a holiday weekend (which translated into T-SQL becomes “Maintenance Window”) and I got bored in between the two or three minutes I had between clicks. So I started a “Twitter” meme – and it just took off. I haven’t cleaned these up much, but here, in author order as of Saturday the 29th of May is the list “You might be a DBA” from around the Twitterverse: buckwoody Your two main enemies are developers and SAN admins #youmightbeaDBA  buckwoody People can use Access as a cross or garlic on you #youmightbeaDBA  buckwoody You always plan an exit strategy, even when entering a McDonald's #youmightbeaDBA  buckwoody You can't explain to your family what you really do for a living #youmightbeaDBA  buckwoody You have at least one set of scripts you won't share #youmightbeaDBA  buckwoody You have an opinion on the best code-beautifier #youmightbeaDBA  buckwoody You have children older than the rest of your team #youmightbeaDBA  buckwoody You and the Oracle DBA would kill each other, but you'll happily fight off a developer together first #youmightbeaDBA  buckwoody You've threatened to quit if they give anyone the sa password on production #youmightbeaDBA  buckwoody You've sent a vendor suggestions on improving their database design or code (and been ignored) #youmightbeaDBA  buckwoody You've sent a vendor suggestions on improving their database design or code (and been ignored) #youmightbeaDBA  buckwoody You have an opinion on the best code-beautifier #youmightbeaDBA  buckwoody You have at least one set of scripts you won't share #youmightbeaDBA  buckwoody You refer to co-workers as "carbon-units" #youmightbeaDBA  buckwoody Being paranoid is on your resume at the top #youmightbeaDBA  buckwoody Everyone comes to your cube to find the MSDN DVD's #youmightbeaDBA  buckwoody You always plan an exit strategy, even when entering a McDonald's #youmightbeaDBA  buckwoody You've worn down developers to get your way by explaining normalization levels #youmightbeaDBA  buckwoody You refer to clothes as "Data Abstractions" #youmightbeaDBA  buckwoody Users pester you to be able to put data in a database, then they pester you to take it out and put it in Excel #youmightbeaDBA  buckwoody Others try to de-duplicate data, you try to copy it to more than three locations #youmightbeaDBA  buckwoody You have at least one DLT tape in the trunk of your car #youmightbeaDBA  buckwoody You use twitter and facebook to talk with colleagues because there's no one else in your company that does what you do #youmightbeaDBA  buckwoody Your spouse knows what "ETL" means #youmightbeaDBA  buckwoody You've referred to yourself as the "Data Janitor" #youmightbeaDBA  buckwoody You don't have positive connotations of the word "upgrade" #youmightbeaDBA  buckwoody You get your coffee before you check your servers, because you know you won't get any if you don't #youmightbeaDBA  buckwoody You always come to work through the back door so no one hijacks you on the way to your cube #youmightbeaDBA  buckwoody You check your server logs before you check your e-mail in the morning so you can reply "Yeah, I already fixed that." #youmightbeaDBA  buckwoody You have more conference badges than clean socks #youmightbeaDBA  buckwoody Your coffee mug says "It depends" #youmightbeaDBA  buckwoody You can convince a boss that you need 16GB of RAM in your laptop #youmightbeaDBA  buckwoody You've used ebay to find production equipment #youmightbeaDBA  buckwoody You pad all project timelines by 2X, and you still miss them #youmightbeaDBA  buckwoody You know when your company is acquiring another even before the CFO #youmightbeaDBA  buckwoody You pad all project timelines by 2X, and you still miss them #youmightbeaDBA  buckwoody You call aspirin "work vitamins" #youmightbeaDBA  buckwoody You get the same amount of sleep even after you have a child #youmightbeaDBA  buckwoody You obsess about performance metrics from over one year ago #youmightbeaDBA  buckwoody The first thing you buy after the database software is aftermarket tools to manage the database software #youmightbeaDBA  buckwoody You've tried to convince someone else to become a DBA #youmightbeaDBA  buckwoody You use twitter and facebook to talk with colleagues because there's no one else in your company that does what you do #youmightbeaDBA  buckwoody You only know other DBA's by their Tweet Handle #youmightbeaDBA  buckwoody You've explained the difference between 32 and 64-bit to more than one manager in terms they can understand, using puppets #youmightbeaDBA  buckwoody Your two main enemies are developers and SAN admins #youmightbeaDBA  buckwoody You've driven to the Datacenter to install SQL Server because "you don't trust those NOC admins" #youmightbeaDBA  buckwoody You pay more for faster Internet connections than cable at home so you don't have to drive in #youmightbeaDBA  buckwoody You call texting a "queuing system" #youmightbeaDBA  buckwoody You know that if someone can read Perl, they manage an Oracle system #youmightbeaDBA  buckwoody You have an e-mail rule for backup notifications #youmightbeaDBA  buckwoody Your food pyramid includes coffee, salt and fat #youmightbeaDBA  buckwoody You wish everything had a graphical query plan #youmightbeaDBA  buckwoody You refactor your e-mails #youmightbeaDBA  buckwoody You've gotten more help from twitter and facebook than all your years in college #youmightbeaDBA  buckwoody You would pay money for a license plate that has the letters S-Q-L together #youmightbeaDBA  buckwoody You have actually considered making a RAID array from thumb drives #youmightbeaDBA  buckwoody Everything on your laptop is installed from your MSDN subscription #youmightbeaDBA  buckwoody You've written blog posts on technology you've never actually implemented in production #youmightbeaDBA  buckwoody Everything on your laptop is installed from your MSDN subscription #youmightbeaDBA  buckwoody @MidnightDBA Click the #youmightbeaDBA tag. I've had WAY too much coffee today.  buckwoody There is no other position that is 1-deep except you and the CEO #youmightbeaDBA  buckwoody When you watch "The Office" you call it "OJT" #youmightbeaDBA  buckwoody You would pay money for a license plate that has the letters S-Q-L together #youmightbeaDBA  buckwoody Your blog would make a "best practices" or "worst practices" book #youmightbeaDBA  buckwoody You have actually considered making a RAID array from thumb drives #youmightbeaDBA  buckwoody The first thing you install on your netbook is SSMS #youmightbeaDBA  buckwoody Everything on your laptop is installed from your MSDN subscription #youmightbeaDBA  buckwoody Your watch is set to UTC because it's just easier #youmightbeaDBA  buckwoody You make plenty of money, but you're excited to get a $2.00 squeeze-ball from Quest and Redgate #youmightbeaDBA  buckwoody You make plenty of money, but you're excited to get a $2.00 squeeze-ball from Quest and Redgate #youmightbeaDBA  buckwoody You think data can be represented as something OTHER than XML #youmightbeaDBA  buckwoody You tell people that you made a database query go faster, and expect them to be happy for you #youmightbeaDBA  buckwoody You take the word "NoSQL" as a personal attack #youmightbeaDBA  buckwoody People can use Access as a cross or garlic on you #youmightbeaDBA  buckwoody * == bad #youmightbeaDBA  buckwoody * == bad #youmightbeaDBA  buckwoody There are just as many females in your technical field as males #youmightbeaDBA  buckwoody People can use Access as a cross or garlic on you #youmightbeaDBA  buckwoody You've gotten more help from twitter and facebook than all your years in college #youmightbeaDBA  buckwoody You think that something OTHER than the database might be the performance bottleneck #youmightbeaDBA  buckwoody You refer to time as a "Clustered Index" #youmightbeaDBA  buckwoody You know why "user" refers to both business people and crack addicts #youmightbeaDBA  buckwoody You make plenty of money, but you're excited to get a $2.00 squeeze-ball from Quest and Redgate #youmightbeaDBA  buckwoody You can't explain to your family what you really do for a living #youmightbeaDBA  buckwoody You tell people that you made a database query go faster, and expect them to be happy for you #youmightbeaDBA  buckwoody You think a millisecond is a really long time #youmightbeaDBA  buckwoody You're sitting and typing #youmightbeaDBA when you could be outside #youmightbeaDBA  buckwoody You can't wait for a technical conference so you can wear a kilt - and you're not Scottish #youmightbeaDBA  buckwoody You know that "DBA" stands for "Default Blame Acceptor" #youmightbeaDBA  buckwoody People can use Access as a cross or garlic on you #youmightbeaDBA  buckwoody You know what "the truth, thole truth and nothing but the truth, so help me Codd" means #youmightbeaDBA  buckwoody You've gotten more help from twitter and facebook than all your years in college #youmightbeaDBA  buckwoody You can't talk fast enough to get a concept out of your head so you tweet it instead #youmightbeaDBA  buckwoody You cry when someone doesn't use a WHERE clause #youmightbeaDBA  buckwoody You think data can be represented as something OTHER than XML #youmightbeaDBA  buckwoody You think "Set theory" is not an verb but a noun #youmightbeaDBA  buckwoody You try to convince random strangers to vote on your Connect item #youmightbeaDBA  buckwoody You think 3 hours of contiguous sleep is a good thing #youmightbeaDBA or #youmightbeamother  buckwoody You don't like Oracle, and not just because of what she did to Neo #youmightbeaDBA  buckwoody You know when to say "sequel" and "s-q-l" #youmightbeaDBA  buckwoody You know where the data is #youmightbeaDBA  buckwoody You refer to your children as "Fully Redundant Mirrors" #youmightbeaDBA  buckwoody Holiday == "Maintenance Window" #youmightbeaDBA  buckwoody Your laptop is more powerful than the servers in most companies - including your own #youmightbeaDBA  buckwoody You capitalize SELECTed words #youmightbeaDBA  buckwoody You take the word "NoSQL" as a personal attack #youmightbeaDBA  buckwoody You know why "user" refers to both business people and crack addicts #youmightbeaDBA  buckwoody You cringe in public when the word "upgrade" is used in a sentence #youmightbeaDBA  buckwoody Holiday == "Maintenance Window" #youmightbeaDBA  buckwoody All Data Is MetaData means something to you #youmightbeaDBA  buckwoody You've never seen the driveway to your house in the daylight #youmightbeaDBA  buckwoody You think that something OTHER than the database might be the performance bottleneck #youmightbeaDBA  buckwoody Most of your bloodstream is composed of caffeine #youmightbeaDBA  buckwoody Your task list is labeled "CRUD Matrix" #youmightbeaDBA  buckwoody You call your wife/husband a "Linked Server" #youmightbeaDBA  anonythemouse When someone tells you they are going to take a dump and you wonder of which database then #youmightbeaDBA  anonythemouse When it's 11pm on a holiday weekend and you are working #youmightbeaDBA  anonythemouse When you sit down at a table and look for it's primary key #youmightbeaDBA  anonythemouse When getting milk from the fridge you check the expiry date is > getdate() #youmightbeaDBA  blakmk when you wake up dreaming about sql #youmightbeaDBA  CharlesGarver You think a @buckwoody bobblehead would be a cool thing to have on the dashboard of your car #youmightbeaDBA  CharlesGarver Your friends don't understand why you think there's a difference between single and double quotes #youmightbeaDBA  CharlesGarver Even the newest employees know your name from all the downtime notices you've sent out #youmightbeaDBA  CharlesGarver You sometimes feel anxious and think "I should test restoring those backups" and then the feeling passes #youmightbeadba  CharlesGarver You know what a co-worker means when they ask "how is your squirrel server?" #youmightbeadba  CharlesGarver You can't sleep at night and you ponder the logisitcs of collecting every copy of Access for the world's biggest bonfire #youmightbeaDBA  CharlesGarver You can't sleep at night and you ponder the logisitcs of collecting every copy of Access for the world's biggest bonfire #youmightbeaDBA  CharlesGarver You're willing to move someone's job up in priority for a box of #voodoodonuts #youmightbeaDBA  CharlesGarver Each person in your company seems to think you work for THEM #youmightbeaDBA  CharlesGarver You have a Love/Hate relationship going on with #Microsoft #youmightbeaDBA  CharlesGarver People ask you to troubleshoot their Access program #youmightbeaDBA  CharlesGarver The first words you hear in the morning are 'your voicemail box is full' #youmightbeaDBA  CharlesGarver The thought of disrupting 500 people's work so you can do something doesn't phase you #youmightbeaDBA  CharlesGarver You can't sleep at night and you ponder the logisitcs of collecting every copy of Access for the world's biggest bonfire #youmightbeaDBA  CharlesGarver Your home computer is backed up in 3 different places #youmightbeaDBA  CharlesGarver Your wardrobe for work includes pajamas #youmightbeaDBA  CharlesGarver Someone tells you to look in the INDEX and you look puzzled before finally going to the back of the book. #youmightbeaDBA  chuckboycejr If you have ever set up a SQLAgent job to email your mobile phone to serve as an alarm clock #youmightbeaDBA  chuckboycejr If you'd rather meet Itzik than Jay Z #youmightbeaDBA  chuckboycejr If you'd rather meet Itzik than Jay Z #youmightbeaDBA  chuckboycejr If you'd wrestle a SysAdmin to the ground to implement #DPA best practices as per @aspiringgeek #youmightbeaDBA  databaseguy I need to be up in 7 hours, so I'm off to bed! I'll have to read the rest of @buckwoody's #youmightbeaDBA posts in the AM. (g'night Buck!)  databaseguy When people ask you about your house, the first thing you describe is the network. #youmightbeaDBA  databaseguy The last thing you say at the office each day is, "is anybody else here? I'm shutting off the lights!" #youmightbeaDBA  databaseguy Your blood pressure rises when you read application specs drafted by marketing. #youmightbeaDBA  databaseguy A good day at work is one when nobody pays you no mind. #youmightbeaDBA  databaseguy You care about latches and wait states. #youmightbeaDBA  databaseguy You have worked over 200 hours on a performance tuning project that required no application changes at all. #youmightbeaDBA  databaseguy The late-night security guard knows the names of your spouse and kids. #youmightbeaDBA  databaseguy You have had vigorous debates about whether it should be pronounced "sequel" or "ess-queue-ell". #youmightbeaDBA  databaseguy You have VPN and RDP software installed on your phone ... just in case. #youmightbeaDBA  databaseguy You have edited a data file by hand, just to see what would happen. #youmightbeaDBA  databaseguy You decorate your office walls with database catalog posters. #youmightbeaDBA  databaseguy You've built programs that access data just to keep other developers from asking you to run queries all the time. #youmightbeaDBA  databaseguy When you watch movies like The Matrix, you find yourself calculating the fasibility of storing all that data. #youmightbeaDBA  databaseguy You have tried to convince someone to spend money on an SSD storage array. #youmightbeaDBA  databaseguy When CPU is spiked on a server, you want to gather forensic evidence. #youmightbeaDBA  databaseguy You have to remind developers not to push code to production without checking if the database is ready. #youmightbeaDBA  databaseguy Nobody cares what you wear to work, as long as the thing keeps running. #youmightbeaDBA  databaseguy Telepathy is a job requirement when working with app dev teams. #youmightbeaDBA  databaseguy You read database statistics for the educational value. #youmightbeaDBA  databaseguy And your boss freely admits this to anyone within earshot. #youmightbeaDBA  databaseguy Your boss cannot explain or understand what you do. #youmightbeaDBA  databaseguy You envision ERDs when you see a GUI. #youmightbeaDBA  databaseguy You say things like "applications come and go, but data lasts forever." #youmightbeaDBA  databaseguy You have memorized the names of several of the AdventureWorks employees. #youmightbeaDBA  databaseguy You know what MAXDOP setting you can get away with for a big query based on current server load. #youmightbeaDBA  databaseguy And you immediately recognize the recursion in my last tweet. #youmightbeaDBA  databaseguy You find 50 simultaneous tweets from @buckwoody about #youmightbeaDBA :O)  DBAishness You have "funny stories" about the times your developers accidentally deleted the T-log in their test environment. #youmightbeaDBA  DBAishness Planning to slice and dice your MDW data with PowerPivot makes you giggle like a schoolgirl. #youmightbeaDBA  donalddotfarmer You think @buckwoody lives in the "real world." #youmightbeaDBA  jamach09 @buckwoody #youmightbeaDBA Why go outside when you can sit in the nice cool server room?  jamach09 If you refer to procreation as "Replication", #youmightbeaDBA.  jamach09 If you think ORM is a four-letter word, #youmightbeaDBA  JamesMarsh If you have ever preached the value of Source Code Control, #YouMightBeADBA  jethrocarr @venzann You store your shopping list in a ACID compliant DB #youmightbeaDBA  joe_positive @buckwoody thought it stood for "Don't Bother Asking" #youmightbeaDBA  joe_positive when you check your IT Events Calendar before making weekend plans #youmightbeaDBA  LadyRuna You cringe whenever someone calls Excel a database #youmightbeaDBA  LadyRuna When the waiter says he'll be your server today, you ask how many terabytes he is #youmightbeaDBA  LadyRuna you always call the asterisk a "Star" #youmightbeaDBA  LadyRuna You walk into a server room, say "Nice RACK!" and everyone there knows you're talking about server rack... #youmightbeaDBA  LadyRuna You receive more messages from servers than from friends #youmightbeaDBA  LadyRuna hmmm... #youmightbeaDBA if your recipe for gumbo is "SELECT * FROM Refrigerator"  markjholmes @SQLSoldier Heh. #youmightbeaDBA if you correct other DBAs' spelling of @PaulRandal  markjholmes #youmightbeaDBA if you actually test RAID5 vs RAID10 on your SAN because when it comes to configuration, "it depends."  markjholmes #youmightbeaDBA if you have at least 3 definitions of the word "cluster"  MarlonRibunal 3 Words: @BrentO, snicker, & Access #youmightbeaDBA  MarlonRibunal @onpnt @mikeSQL my appeal was a couple of mins late. Enjoying #youmightbeaDBA  MarlonRibunal @mikeSQL @onpnt pls, don't mention bacon #youmightbeaDBA  merv @buckwoody You HATE 3-way joins #youmightbeaDBA  MidnightDBA If you're up at midnight Tweeting about SQL #youmightbeaDBA  MidnightDBA @buckwoody I'd noticed that. :) #youmightbeaDBA  mikeSQL when people talk about "their type" you're thinking varchar, bigint, binary, etc #youmightbeadba  mikeSQL people ask you to go to lunch , but you can't go because you're attending #SQLlunch #youmightbeadba  mikeSQL you laugh for hours at all of the #sqlmoviequotes ....things in which a normal individual would scratch their head at. #youmightbeadba  mikeSQL you laugh for hours at all of the #sqlmoviequotes ....things in which a normal individual would scratch their head at. #youmightbeadba  mrdenny If you think that @buckwoody's demo using PowerPivot to analyze index usage data from DMVs is awesome then #youmightbeaDBA  mrdenny You wish @PaulRandal still worked at Microsoft so that they would make a bobble head of him #youmightbeadba  mrdenny When it's 11pm on a holiday weekend, and your posting stupid jokes on Twitter then #youmightbeadba  mrdenny If you go out with friends and wonder why no one's wearing a kilt then #YouMightBeADBA  mrdenny You can't do basic math, but you know off the top of your head how many CALs $14,412 can buy you. #YoumightbeaDBA  mrdenny If you've ever setup a SQL Job to email you to get you out of a regularly scheduled meeting #YouMightBeADBA.  mrdenny You throw up in your mouth a little when ever you here the word "Access". Even if it doesn't relate to a MS product. #YouMightBeADBA  msdtjones You spend more time listening to @buckwoody than your wife #youmightbeaDBA  NFDotCom You perform "hail deltas" on a regular basis. #YouMightBeADBA  NoelMcKinney If you tell your wife you want to go to Columbus Ohio for your wedding anniversary so you can attend #sqlsat42 then #youmightbeaDBA  NoelMcKinney You read a union is on strike and wonder if it's a UNION ALL #youmightbeaDBA  NoelMcKinney You read a union is on strike and wonder if it's a UNION ALL #youmightbeaDBA  NoelMcKinney Someone asks you to throw another log on the fire and you tell them not to worry about it because Autogrowth is turned on #youmightbeaDBA  Nuurdygirl Even if you have a girlfriend...its possible #youmightbeadba. Yeah-i said its possible!  Nuurdygirl When your girlfriend has to lean around the laptop to kiss you goodnight #youmightbeadba  Old_Man_Fish If you worry about how big your package is and how long it takes to finish #youmightbeaDBA  Old_Man_Fish If you no longer wonder if someone is in trouble or died if you are getting calls at 2AM #youmightbeaDBA  Old_Man_Fish If, when you hear the word ACCESS with no connotation you blood pressure jumps 50 points, #youmightbeaDBA  onpnt When you hear the word inject you immediately get concerned if your databases are OK #youmightbeaDBA  onpnt Your servers haven't been rebooted in a year #youmightbeaDBA  onpnt You know why it's funny when @PaulRandal has the word, "Sheep" in a tweet #youmightbeaDBA  onpnt You have read BOL without actually having a problem to figure out #youmightbeaDBA  onpnt You can type "SELECT columns FROM tables" without typos but tipen ni Banglish ares a messis #youmightbeaDBA  onpnt DR strategies doesn't include the word, RAID in them #youmightbeaDBA  onpnt you can move a SQL Server instance to a new server without the users ever knowing #youmightbeaDBA  onpnt You have made an SSIS package that is more than one step #youmightbeaDBA  onpnt You have the balls to say no to your boss when they ask for the sa password #youmightbeaDBA  onpnt you google to trouble shoot a problem and end up at your own blog (and it fixes it) #youmightbeaDBA  onpnt You talk your wife into moving the family vacation a week earlier so you can attend the areas local SSUG meeting #youmightbeaDBA  onpnt you can explain to a nontechnical person what a deadlock is #youmightbeaDBA  onpnt You hope a girl asks you what your collation is #youmightbeaDBA  onpnt you make jokes that include the words shrink, truncate and 1205. And you are the only one that laughs at them #youmightbeaDBA  onpnt You rate your ability to stay awake to work longer on blogs, twitter, forums and your day to day job with the 5 9's goal #youmightbeaDBA  onpnt you have major surgery and beg the doctor to release you back to work 5 days later because you miss your servers #youmightbeaDBA #TrueStory  onpnt You do have backups and you know how to use them #youmightbeaDBA  onpnt It's the network #youmightbeaDBA  onpnt When the developers get to work your mood changes rapidly #youmightbeaDBA  onpnt When someone says, "PASS", you first think of karaoke #youmightbeaDBA  onpnt Recruiters try to get you to call them *just* because they think you'll give them @BrentO contact info #youmightbeaDBA  onpnt You chuckle every time you go to grab the "CLR" Calcium, Lime and Rust Remover to clean something #youmightbeaDBA  onpnt @MarlonRibunal @mikeSQL Sorry man, it was already in motion ;-) #youmightbeaDBA  onpnt When you have an "I love bacon" sticker on your laptop. #youmightbeaDBA http://twitpic.com/1ry671  onpnt You sing SELECT statements in the shower #youmightbeaDBA  onpnt When you see a chicken it doesn't remind you of food. It reminds you of a guy named Jorge #youmightbeaDBA  onpnt At time, SQL is your mistress #youmightbeaDBA  onpnt Your wife wonders if SQL is the code name of your mistress at times #youmightbeaDBA  onpnt it's Friday and you are on twitter thinking really hard about what would be funny for hash tag #youmightbeaDBA  onpnt You organize your wife's "decorative"pillows on the bed in a B-Tree structure #youmightbeaDBA  PaulWhiteNZ If you: SELECT TOP (1) milk FROM fridge WHERE use_by_date >= GET_DATE() ORDER BY use_by_date ASC #YouMightBeaDBA  RonDBA #youmightbeaDBA if you read @buckwoody's and @BrentO's blogs.  ryaneastabrook @buckwoody omg, you have to stand up a website with these on them, they are awesome #youmightbeaDBA  soulvy @StrateSQL @LadyRuna Or a "Splat" #youmightbeaDBA  speedracer You can still fall asleep after three cups of coffee #youmightbeaDBA  speedracer You retweet @buckwoody on a Friday night #youmightbeaDBA  speedracer You can still fall asleep after three cups of coffee #youmightbeaDBA  speedracer Developers make you twitch #youmightbeaDBA  sqlagentman You know what X/1024*8 is. #YouMightBeADBA  SqlAsylum Your still in the office at 5:00 on memorial day weekend. #youmightbeadba :)  SQLBob Whenever someone you know gets pregnant you bring up INNER JOINs or SQL Injection attacks... #youmightbeaDBA  SQLChicken You know one or more SQL folks in the community with an animal in their username #youmightbeaDBA  SQLChicken You've used one or more car analogies to explain how a database works #youmightbeaDBA  SQLChicken “@sqljoe: #youmightbeaDBA if you applied to attend #sqlu and requested @SQLChicken to pull strings for you” lmao nice!  SQLChicken When talking about SSIS your discussions break down into various jokes about packages #youmightbeaDBA  SQLChicken Just SEEING the code for cursors makes you break out in hives #youmightbeaDBA  SQLChicken Just SEEING the code for cursors makes you break out in hives #youmightbeaDBA  SQLCraftsman You coined the phrase "Magic SAN Dust" because calling a vendor's marketing claims BS is not acceptable in a meeting. #YouMightBeADBA  SQLCraftsman If you hear about a new feature with the acronym "DAC" and wonder what disaster of a feature it is attached to this time. #YouMightBeADBA  SQLCraftsman You really own a "Stick of Much Developer Whacking" #YouMightBeADBA  SQLCraftsman You coined the phrase "Magic SAN Dust" because calling a vendor's marketing claims BS is not acceptable in a meeting. #YouMightBeADBA  SQLCraftsman Default Blame Acceptor #YouMightBeADBA  SQLCraftsman If you hear about a new feature with the acronym "DAC" and wonder what disaster of a feature it is attached to this time. #YouMightBeADBA  SQLCraftsman Default Blame Acceptor #YouMightBeADBA  SQLCraftsman If you hear about a new feature with the acronym "DAC" and wonder what disaster of a feature it is attached to this time. #YouMightBeADBA  sqljoe #youmightbeaDBA if you wished your wife knew T-sql. USE ShoppingList SELECT NecessaryItems from Supermarket WHERE Category<> ("junk food")  sqljoe #youmightbeaDBA if the first thing you kiss when you wake up is your mobile for not waking you up in the middle of the night  sqljoe #youmightbeaDBA if your wife has a "Do Not Fly" family vacation list of her own including your laptop and mobile  sqljoe #youmightbeaDBA if you have researched for DBA Anonymous groups and attended a #SSUG willing to drop your database (vice)  sqljoe #youmightbeaDBA if your only maintenance windows are staff meetings  sqljoe #youmightbeaDBA if you think of yourself as "The One" in The Matrix "balancing the equation" from The Architect's (developers) poor coding  sqljoe #youmightbeaDBA if you think @PaulRandal should have played the Oracle in The Matrix  sqljoe #youmightbeaDBA if home CD & Movie collection is stored in secured containers,in logical order & naming convention,and with a backup copy  sqljoe #youmightbeaDBA if you applied to attend #sqlu and requested @SQLChicken to pull strings for you  sqljoe #youmightbeaDBA if you have tried to TiVo @MidnightDBA broadcasts  sqljoe #youmightbeaDBA if your #sql user group feels like #AA meetings  sqljoe #youmightbeaDBA if you thought of bringing your #sql books to #sqlsaturday and #sqlpass for autographs  sqljoe #youmightbeaDBA if #sqlpass feels like the #oscars  sqljoe #youmightbeaDBA if you are proud of your small package  SQLLawman #youmightbeaDBA when you hear MDX and Acura is not first thought that comes to mind.  sqlrunner If your wife double checks that there isn't a SQLSat within 200 miles of your vacation destination #youmightbeaDBA  sqlrunner When you're on a conference call and your wife thinks your speaking in a foreign language #youmightbeaDBA  sqlrunner When you're on a conference call and your wife thinks your speaking in a foreign language #youmightbeaDBA  sqlrunner You treat the word 'access' as a verb, not a noun #youmightbeaDBA  sqlrunner If you are happy with sub-second performance #youmightbeaDBA  sqlrunner When you know the names of the NOC people AND their families #youmightbeadba  sqlrunner When you know the names of the NOC people AND their families #youmightbeadba  sqlrunner Your company set's up international phone coverage for your cruise #youmightbeaDBA  sqlsamson @buckwoody if your manager asks you for data and you respond with "there's a script for that" #youmightbeadba  sqlsamson @buckwoody If you receive more messages from your server then your spouse #youmightbeadba  SQLSoldier You've spent all night Valentines Day upgrading the SQL Servers and forgot to tell your wife you'd be working late. #youmightbeadba  SQLSoldier You're flattered when someone calls you a geek. #youmightbeadba  SQLSoldier @llangit @mrdenny it's 11pm on a holiday weekend, & your reading stupid jokes on Twitter then #youmightbeadba  SQLSoldier Your manager borrows lunch money from you because your salary is 30% higher than his. #youmightbeaDBA  SQLSoldier You think "intellisense" is a double negative because it's not intelligent nor makes sense. #youmightbeaDBA  SQLSoldier 75% of the emails you receive at home have the phrase "now following you on Twitter!" in the subject line. #youmightbeaDBA  SQLSoldier You petition Ken Burns to remake Office Space because it should have been 18 hours long. #youmightbeaDBA  SQLSoldier You select a candidate for a Jr DBA position because his resume said he's willing to get your coffee. #youmightbeaDBA  SQLSoldier Somebody misquotes @PaulRandall and you call him on your cell to verify. #youmightbeaDBA  SQLSoldier You wish the elevator in your building was slower because it's the last time you'll be left alone all day. #youmightbeaDBA  SQLSoldier The developers sacrifice small animals before giving you their code for review. #youmightbeaDBA  SQLSoldier Developers bring you coffee and a BLT when you review their code. #youmightbeaDBA #IWish  SQLSoldier You can get out of any family get-together by saying you have to work and nobody questions it. #youmightbeaDBA  SQLSoldier You've requested a HP Superdome for you "test" box. #youmightbeaDBA  SQLSoldier Your leave work early because your internet connection to the data center is better at home #youmightbeaDBA  SQLSoldier The new CEO asks you to justify your salary, so you go on vacation for 2 weeks. And he never questions you again. #youmightbeaDBA  SQLSoldier You cheer when Milton burns down the company in Office Space #youmightbeaDBA  SQLSoldier A dev. asks if you've heard about some great new feature in SQL and you show the 16 blog posts you wrote on it ... last year #youmightbeaDBA  SQLSoldier Your dev team is still testing SQL 2008 and you're already planning for SQL 11. #youmightbeaDBA #TrueStory  SQLSoldier The new CEO asks you to justify your salary, so you go on vacation for 2 weeks. And he never questions you again. #youmightbeaDBA  SQLSoldier Your dev team is still testing SQL 2008 and you're already planning for SQL 11. #youmightbeaDBA  SQLSoldier You use a cell phone service coverage map to plan your next vacation. #youmightbeaDBA  SQLSoldier You come in to work at 7 AM because it gives you at least 3 hours without any developers around. #youmightbeaDBA  SQLSoldier You figure out a way to make take your wife on a cruise and deduct it as a business expense. #youmightbeaDBA #sqlcruise  SQLSoldier You name your cat SQLDog because the name @SQLCat was already taken. #youmightbeaDBA  SQLSoldier You rate your blog posts based on the number of retweets you get. #youmightbeaDBA  SQLSoldier You disable random logins just to mess with people. #youmightbeaDBA  SQLSoldier You fall for the pickup line, "Hey baby, what's your collation?" #youmightbeaDBA  SQLSoldier You can blame an outage on anyone in the company because you're the only one that knows how to find out what really happened #youmightbeaDBA  SQLSoldier You can blame an outage on anyone in the company because you're the only one that knows how to find out what really happened #youmightbeaDBA  SQLSoldier You cheer when Milton burns down the company in Office Space #youmightbeaDBA  SQLSoldier Your leave work early because your internet connection to the data center is better at home #youmightbeaDBA  SQLSoldier You cheer when Milton burns down the company in Office Space #youmightbeaDBA  SQLSoldier Your think the 4 food groups are coffee, bacon, fast food, and Mountain Dew. #youmightbeaDBA  SQLSoldier You tell someone your job title and they ask "What?" You describe it and they ask "What?". So you say "computer geek". #youmightbeaDBA  SQLSoldier The #1 referrer to your blog is Twitter.com. #youmightbeaDBA  SQLSoldier Your idea of a good time on a Saturday involves free training. #youmightbeaDBA #sqlsat43  SQLSoldier You write a book that all of your co-workers have and none have read it. #youmightbeaDBA  SQLSoldier You write a book that sells a couple thousand copies and is heralded a best seller. #youmightbeaDBA  SQLSoldier No matter how sick you are, you go to work if it's time to pass the pager on to the next guy. #youmightbeaDBA #TrueStory  SQLSoldier You go out on the town, and strangers walk up to you and say, "Hey you're that SQL guy" #youmightbeaDBA #TrueStory  SQLSoldier Your wife asks you to fix something, and you request a downtime window. #youmightbeaDBA  SQLSoldier Your wife asks when you'll be home, and you tell her that you wish you knew. #youmightbeaDBA  SQLSoldier Your best pickup line, "Hey baby, what's your collation?" #youmightbeaDBA  SQLSoldier Your wife asks when you'll be home, and you tell her that you wish you knew. #youmightbeaDBA  SQLSoldier You know that @BuckWoody is not someone's porno name. #youmightbeaDBA  SQLSoldier You list TSQL as your native language on the 2010 census. #youmightbeaDBA  SQLSoldier Starbucks' stock price drops every time you go on vacation. #youmightbeaDBA  SQLSoldier You're happy when the web master says that the website is down. #youmightbeaDBA  SQLSoldier You know that @BuckWoody is not someone's porno name. #youmightbeaDBA  SQLSoldier You get mad when someone calls your car a "heap" because you've always considered it to be a "clustered index". #youmightbeaDBA  SQLSoldier Your blog has more hits than your company's website. #youmightbeaDBA  SQLSoldier You systematically remove the asterisk key from all keyboards in the company except yours. #youmightbeaDBA  SQLSoldier When asked if you recycle, you reply that you run sp_cycle_errorlog every night at midnight #youmightbeaDBA  SQLSoldier You wouldn't allow someone named @AdamMachanic to work on your car. #youmightbeaDBA  SQLSoldier You switch offices every 3 days to avoid developers #youmightbeaDBA  SQLSoldier PSS has your number on speed dial. #youmightbeaDBA  SQLSoldier You frown when you they tell Neo that he's going to the Oracle #youmightbeaDBA  swhaley you regretted saying "This shouldn't effect production" #youmightbeaDBA  swhaley you regretted saying "This shouldn't effect production" #youmightbeaDBA  Tarwn A pleasurable saturday means spending the day learning more about what you already do the rest of the week #youmightbeaDBA ...oh, wait...  thelostforum For great justice; all our base are belong to YOU !! #youmightbeadba  thelostforum @SQLSoldier: You need a witness to use a mirror #youmightbeaDBA ;)  TimCost you capitalize key words. always. everywhere. you can't help it, usually don't even notice. #youmightbeaDBA  Toshana Your the only one in your company not impressed with the developers new application. #youmightbeaDBA  venzann Coming soon from a (respected) book publisher - @buckwoody's #youmightbeaDBA  venzann He's on a role tonight. @buckwoody is summing up my life with his #youmightbeaDBA tweets...  venzann I love the #youmightbeaDBA tag. Found at least 6 new DBAs to follow..  venzann He's on a role tonight. @buckwoody is summing up my life with his #youmightbeaDBA tweets...  venzann You use #sqlhelp as a primary resource during troubleshooting #youmightbeaDBA  venzann You insist on stricter password security for your sql servers than you implement on your own laptop #youmightbeaDBA  WesBrownSQL @buckwoody you are up so late the only tweets you see are from @buckwoody #youmightbeaDBA  WesBrownSQL @SQLSoldier you are upgrading all your 2005 prod servers to 2008 R2 on a three day weekend... #youmightbeaDBA  zippy1981 #youmightbeaDBA if everytime you do something with #mongodb you think of the Vulcan proverb "only Nixon could go to China."  Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • How to make a table that looks like this in html or make a tableless one

    - by Sithelo
    I have a to present data in html with headers. Below is the image of part of the header which i am struggling with. I have managed to rotate the text but the problem is there overlap. This is the code of the whole structure. <style type="text/css"> .text-rotation { -webkit-transform: rotate(90deg); -moz-transform: rotate(90deg); filter: progid:DXImageTransform.Microsoft.BasicImage(rotation=1); -ms-filter: "progid:DXImageTransform.Microsoft.BasicImage(rotation=1)"; height:inherit; } </style> </head> <body> <table width="100%" border="1" align="center" cellpadding="3" cellspacing="1"> <tr> <td rowspan="5">&nbsp;</td> <td rowspan="5" align="center" valign="bottom">Code</td> <td rowspan="5" align="center" valign="bottom">Change</td> <td rowspan="5" align="center" valign="bottom">Description</td> <td colspan="6" align="center" bgcolor="#FF6666">STOCK RANGE</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> </tr> <tr> <td colspan="2" align="center" bgcolor="#66CC00" >SPHERICAL</td> <td colspan="2" align="center" bgcolor="#FFCC00" >SPH/CYL-/-</td> <td colspan="2" align="center" bgcolor="#0066CC">SPH/CYL+/-</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> </tr> <tr> <td rowspan="3" align="center" bgcolor="#66CC00" class="text-rotation">MINUS</td> <td rowspan="3" align="center" bgcolor="#66CC00" class="text-rotation">PLUS</td> <td rowspan="3" align="center" bgcolor="#FFCC00" class="text-rotation">MINUS</td> <td rowspan="3" align="center" bgcolor="#FFCC00" class="text-rotation">PLUS</td> <td rowspan="3" align="center" bgcolor="#0066CC" class="text-rotation">PLUS</td> <td rowspan="3" align="center" bgcolor="#0066CC" class="text-rotation">MINUS</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> </tr> <tr> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> </tr> <tr> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> </tr> <tr> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> <td>&nbsp;</td> </tr> </table> </body>

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  • RHEL 5.5 Yum Update Fails Dependency Error

    - by user65788
    I have 30 different RHEL 5.5 machines that will not update some 33 packages via Yum. Does anyone know why these packages will not install and how to correct this? Yum clean all does not fix the issue, however skip broken will allow other updates to install but I am really after a way to clear this up for good. They are stock boxes with RHEL subscription and not using any yum repositories other than Red Hat's own official repositories. They have not been updated for over a year! yum update Loaded plugins: rhnplugin, security rhel-i386-client-5 | 1.4 kB 00:00 rhel-i386-client-5/primary | 2.8 MB 00:09 rhel-i386-client-5 6607/6607 Skipping security plugin, no data Setting up Update Process Resolving Dependencies Skipping security plugin, no data --> Running transaction check ---> Package autofs.i386 1:5.0.1-0.rc2.143.el5_5.6 set to be updated ---> Package cpp.i386 0:4.1.2-48.el5 set to be updated --> Processing Dependency: curl = 7.15.5-2.1.el5_3.5 for package: curl-devel ---> Package curl.i386 0:7.15.5-9.el5 set to be updated --> Processing Dependency: cyrus-sasl-lib = 2.1.22-5.el5 for package: cyrus-sasl-devel ---> Package cyrus-sasl-lib.i386 0:2.1.22-5.el5_4.3 set to be updated ---> Package cyrus-sasl-md5.i386 0:2.1.22-5.el5_4.3 set to be updated ---> Package cyrus-sasl-plain.i386 0:2.1.22-5.el5_4.3 set to be updated --> Processing Dependency: db4 = 4.3.29-10.el5 for package: db4-devel ---> Package db4.i386 0:4.3.29-10.el5_5.2 set to be updated --> Processing Dependency: dbus = 1.1.2-12.el5 for package: dbus-devel ---> Package dbus.i386 0:1.1.2-14.el5 set to be updated ---> Package dbus-libs.i386 0:1.1.2-14.el5 set to be updated ---> Package dbus-x11.i386 0:1.1.2-14.el5 set to be updated ---> Package e2fsprogs.i386 0:1.39-23.el5_5.1 set to be updated --> Processing Dependency: e2fsprogs-libs = 1.39-23.el5 for package: e2fsprogs-devel ---> Package e2fsprogs-libs.i386 0:1.39-23.el5_5.1 set to be updated ---> Package esc.i386 0:1.1.0-12.el5 set to be updated --> Processing Dependency: expat = 1.95.8-8.2.1 for package: expat-devel ---> Package expat.i386 0:1.95.8-8.3.el5_5.3 set to be updated ---> Package firefox.i386 0:3.6.13-2.el5 set to be updated --> Processing Dependency: freetype = 2.2.1-21.el5_3 for package: freetype-devel ---> Package freetype.i386 0:2.2.1-28.el5_5.1 set to be updated --> Processing Dependency: gcc = 4.1.2-46.el5_4.1 for package: gcc-c++ --> Processing Dependency: gcc = 4.1.2-46.el5_4.1 for package: gcc-gfortran ---> Package gcc.i386 0:4.1.2-48.el5 set to be updated --> Processing Dependency: gd = 2.0.33-9.4.el5_1.1 for package: gd-devel ---> Package gd.i386 0:2.0.33-9.4.el5_4.2 set to be updated --> Processing Dependency: gnome-vfs2 = 2.16.2-4.el5 for package: gnome-vfs2-devel ---> Package gnome-vfs2.i386 0:2.16.2-6.el5_5.1 set to be updated ---> Package gnome-vfs2-smb.i386 0:2.16.2-6.el5_5.1 set to be updated --> Processing Dependency: gnutls = 1.4.1-3.el5_3.5 for package: gnutls-devel ---> Package gnutls.i386 0:1.4.1-3.el5_4.8 set to be updated --> Processing Dependency: gtk2 = 2.10.4-20.el5 for package: gtk2-devel ---> Package gtk2.i386 0:2.10.4-21.el5_5.6 set to be updated --> Processing Dependency: hal = 0.5.8.1-52.el5 for package: hal-devel ---> Package hal.i386 0:0.5.8.1-59.el5 set to be updated --> Processing Dependency: krb5-libs = 1.6.1-36.el5 for package: krb5-devel ---> Package krb5-libs.i386 0:1.6.1-36.el5_5.6 set to be updated ---> Package krb5-workstation.i386 0:1.6.1-36.el5_5.6 set to be updated --> Processing Dependency: libXi = 1.0.1-3.1 for package: libXi-devel ---> Package libXi.i386 0:1.0.1-4.el5_4 set to be updated --> Processing Dependency: libXrandr = 1.1.1-3.1 for package: libXrandr-devel ---> Package libXrandr.i386 0:1.1.1-3.3 set to be updated --> Processing Dependency: libXt = 1.0.2-3.1.fc6 for package: libXt-devel ---> Package libXt.i386 0:1.0.2-3.2.el5 set to be updated --> Processing Dependency: libgfortran = 4.1.2-46.el5_4.1 for package: gcc-gfortran ---> Package libgfortran.i386 0:4.1.2-48.el5 set to be updated --> Processing Dependency: libsepol = 1.15.2-2.el5 for package: libsepol-devel ---> Package libsepol.i386 0:1.15.2-3.el5 set to be updated --> Processing Dependency: libstdc++ = 4.1.2-46.el5_4.1 for package: gcc-c++ --> Processing Dependency: libstdc++ = 4.1.2-46.el5_4.1 for package: libstdc++-devel ---> Package libstdc++.i386 0:4.1.2-48.el5 set to be updated --> Processing Dependency: mesa-libGL = 6.5.1-7.7.el5 for package: mesa-libGL-devel ---> Package mesa-libGL.i386 0:6.5.1-7.8.el5 set to be updated --> Processing Dependency: mesa-libGLU = 6.5.1-7.7.el5 for package: mesa-libGLU-devel ---> Package mesa-libGLU.i386 0:6.5.1-7.8.el5 set to be updated --> Processing Dependency: newt = 0.52.2-12.el5_4.1 for package: newt-devel ---> Package newt.i386 0:0.52.2-15.el5 set to be updated --> Processing Dependency: nspr = 4.7.6-1.el5_4 for package: nspr-devel ---> Package nspr.i386 0:4.8.6-1.el5 set to be updated --> Processing Dependency: nss = 3.12.3.99.3-1.el5_3.2 for package: nss-devel ---> Package nss.i386 0:3.12.8-1.el5 set to be updated ---> Package nss-tools.i386 0:3.12.8-1.el5 set to be updated --> Processing Dependency: openldap = 2.3.43-3.el5 for package: openldap-devel ---> Package openldap.i386 0:2.3.43-12.el5_5.3 set to be updated ---> Package openldap-clients.i386 0:2.3.43-12.el5_5.3 set to be updated --> Processing Dependency: openssl = 0.9.8e-12.el5 for package: openssl-devel ---> Package openssl.i686 0:0.9.8e-12.el5_5.7 set to be updated --> Processing Dependency: pam = 0.99.6.2-6.el5 for package: pam-devel ---> Package pam.i386 0:0.99.6.2-6.el5_5.2 set to be updated --> Processing Dependency: popt = 1.10.2.3-18.el5 for package: rpm-devel --> Processing Dependency: popt = 1.10.2.3-18.el5 for package: rpm-build ---> Package popt.i386 0:1.10.2.3-20.el5_5.1 set to be updated --> Processing Dependency: python = 2.4.3-27.el5 for package: python-devel ---> Package python.i386 0:2.4.3-27.el5_5.3 set to be updated --> Processing Dependency: rpm = 4.4.2.3-18.el5 for package: rpm-devel --> Processing Dependency: rpm = 4.4.2.3-18.el5 for package: rpm-build ---> Package rpm.i386 0:4.4.2.3-20.el5_5.1 set to be updated --> Processing Dependency: rpm-libs = 4.4.2.3-18.el5 for package: rpm-devel --> Processing Dependency: rpm-libs = 4.4.2.3-18.el5 for package: rpm-build ---> Package rpm-libs.i386 0:4.4.2.3-20.el5_5.1 set to be updated ---> Package rpm-python.i386 0:4.4.2.3-20.el5_5.1 set to be updated ---> Package xulrunner.i386 0:1.9.2.13-3.el5 set to be updated ---> Package xulrunner-devel.i386 0:1.9.2.7-2.el5 set to be updated --> Processing Dependency: xulrunner = 1.9.2.7-2.el5 for package: xulrunner-devel --> Processing Dependency: nss-devel >= 3.12.6 for package: xulrunner-devel --> Processing Dependency: nspr-devel >= 4.8 for package: xulrunner-devel --> Processing Dependency: libnotify-devel for package: xulrunner-devel ---> Package yelp.i386 0:2.16.0-26.el5 set to be updated rhel-i386-client-5/filelists | 16 MB 00:45 --> Finished Dependency Resolution xulrunner-devel-1.9.2.7-2.el5.i386 from rhel-i386-client-5 has depsolving problems --> Missing Dependency: libnotify-devel is needed by package xulrunner-devel-1.9.2.7-2.el5.i386 (rhel-i386-client-5) mesa-libGLU-devel-6.5.1-7.7.el5.i386 from installed has depsolving problems --> Missing Dependency: mesa-libGLU = 6.5.1-7.7.el5 is needed by package mesa-libGLU-devel-6.5.1-7.7.el5.i386 (installed) python-devel-2.4.3-27.el5.i386 from installed has depsolving problems --> Missing Dependency: python = 2.4.3-27.el5 is needed by package python-devel-2.4.3-27.el5.i386 (installed) nss-devel-3.12.3.99.3-1.el5_3.2.i386 from installed has depsolving problems --> Missing Dependency: nss = 3.12.3.99.3-1.el5_3.2 is needed by package nss-devel-3.12.3.99.3-1.el5_3.2.i386 (installed) libstdc++-devel-4.1.2-46.el5_4.1.i386 from installed has depsolving problems --> Missing Dependency: libstdc++ = 4.1.2-46.el5_4.1 is needed by package libstdc++-devel-4.1.2-46.el5_4.1.i386 (installed) xulrunner-devel-1.9.2.7-2.el5.i386 from rhel-i386-client-5 has depsolving problems --> Missing Dependency: nspr-devel >= 4.8 is needed by package xulrunner-devel-1.9.2.7-2.el5.i386 (rhel-i386-client-5) gcc-c++-4.1.2-46.el5_4.1.i386 from installed has depsolving problems --> Missing Dependency: libstdc++ = 4.1.2-46.el5_4.1 is needed by package gcc-c++-4.1.2-46.el5_4.1.i386 (installed) rpm-devel-4.4.2.3-18.el5.i386 from installed has depsolving problems --> Missing Dependency: rpm-libs = 4.4.2.3-18.el5 is needed by package rpm-devel-4.4.2.3-18.el5.i386 (installed) xulrunner-devel-1.9.2.7-2.el5.i386 from rhel-i386-client-5 has depsolving problems --> Missing Dependency: xulrunner = 1.9.2.7-2.el5 is needed by package xulrunner-devel-1.9.2.7-2.el5.i386 (rhel-i386-client-5) nspr-devel-4.7.6-1.el5_4.i386 from installed has depsolving problems --> Missing Dependency: nspr = 4.7.6-1.el5_4 is needed by package nspr-devel-4.7.6-1.el5_4.i386 (installed) libXrandr-devel-1.1.1-3.1.i386 from installed has depsolving problems --> Missing Dependency: libXrandr = 1.1.1-3.1 is needed by package libXrandr-devel-1.1.1-3.1.i386 (installed) libsepol-devel-1.15.2-2.el5.i386 from installed has depsolving problems --> Missing Dependency: libsepol = 1.15.2-2.el5 is needed by package libsepol-devel-1.15.2-2.el5.i386 (installed) libXt-devel-1.0.2-3.1.fc6.i386 from installed has depsolving problems --> Missing Dependency: libXt = 1.0.2-3.1.fc6 is needed by package libXt-devel-1.0.2-3.1.fc6.i386 (installed) mesa-libGL-devel-6.5.1-7.7.el5.i386 from installed has depsolving problems --> Missing Dependency: mesa-libGL = 6.5.1-7.7.el5 is needed by package mesa-libGL-devel-6.5.1-7.7.el5.i386 (installed) openldap-devel-2.3.43-3.el5.i386 from installed has depsolving problems --> Missing Dependency: openldap = 2.3.43-3.el5 is needed by package openldap-devel-2.3.43-3.el5.i386 (installed) openssl-devel-0.9.8e-12.el5.i386 from installed has depsolving problems --> Missing Dependency: openssl = 0.9.8e-12.el5 is needed by package openssl-devel-0.9.8e-12.el5.i386 (installed) dbus-devel-1.1.2-12.el5.i386 from installed has depsolving problems --> Missing Dependency: dbus = 1.1.2-12.el5 is needed by package dbus-devel-1.1.2-12.el5.i386 (installed) newt-devel-0.52.2-12.el5_4.1.i386 from installed has depsolving problems --> Missing Dependency: newt = 0.52.2-12.el5_4.1 is needed by package newt-devel-0.52.2-12.el5_4.1.i386 (installed) gnome-vfs2-devel-2.16.2-4.el5.i386 from installed has depsolving problems --> Missing Dependency: gnome-vfs2 = 2.16.2-4.el5 is needed by package gnome-vfs2-devel-2.16.2-4.el5.i386 (installed) gnutls-devel-1.4.1-3.el5_3.5.i386 from installed has depsolving problems --> Missing Dependency: gnutls = 1.4.1-3.el5_3.5 is needed by package gnutls-devel-1.4.1-3.el5_3.5.i386 (installed) rpm-build-4.4.2.3-18.el5.i386 from installed has depsolving problems --> Missing Dependency: rpm-libs = 4.4.2.3-18.el5 is needed by package rpm-build-4.4.2.3-18.el5.i386 (installed) gd-devel-2.0.33-9.4.el5_1.1.i386 from installed has depsolving problems --> Missing Dependency: gd = 2.0.33-9.4.el5_1.1 is needed by package gd-devel-2.0.33-9.4.el5_1.1.i386 (installed) e2fsprogs-devel-1.39-23.el5.i386 from installed has depsolving problems --> Missing Dependency: e2fsprogs-libs = 1.39-23.el5 is needed by package e2fsprogs-devel-1.39-23.el5.i386 (installed) xulrunner-devel-1.9.2.7-2.el5.i386 from rhel-i386-client-5 has depsolving problems --> Missing Dependency: nss-devel >= 3.12.6 is needed by package xulrunner-devel-1.9.2.7-2.el5.i386 (rhel-i386-client-5) krb5-devel-1.6.1-36.el5.i386 from installed has depsolving problems --> Missing Dependency: krb5-libs = 1.6.1-36.el5 is needed by package krb5-devel-1.6.1-36.el5.i386 (installed) gcc-gfortran-4.1.2-46.el5_4.1.i386 from installed has depsolving problems --> Missing Dependency: libgfortran = 4.1.2-46.el5_4.1 is needed by package gcc-gfortran-4.1.2-46.el5_4.1.i386 (installed) curl-devel-7.15.5-2.1.el5_3.5.i386 from installed has depsolving problems --> Missing Dependency: curl = 7.15.5-2.1.el5_3.5 is needed by package curl-devel-7.15.5-2.1.el5_3.5.i386 (installed) pam-devel-0.99.6.2-6.el5.i386 from installed has depsolving problems --> Missing Dependency: pam = 0.99.6.2-6.el5 is needed by package pam-devel-0.99.6.2-6.el5.i386 (installed) rpm-build-4.4.2.3-18.el5.i386 from installed has depsolving problems --> Missing Dependency: rpm = 4.4.2.3-18.el5 is needed by package rpm-build-4.4.2.3-18.el5.i386 (installed) expat-devel-1.95.8-8.2.1.i386 from installed has depsolving problems --> Missing Dependency: expat = 1.95.8-8.2.1 is needed by package expat-devel-1.95.8-8.2.1.i386 (installed) gcc-c++-4.1.2-46.el5_4.1.i386 from installed has depsolving problems --> Missing Dependency: gcc = 4.1.2-46.el5_4.1 is needed by package gcc-c++-4.1.2-46.el5_4.1.i386 (installed) gtk2-devel-2.10.4-20.el5.i386 from installed has depsolving problems --> Missing Dependency: gtk2 = 2.10.4-20.el5 is needed by package gtk2-devel-2.10.4-20.el5.i386 (installed) gcc-gfortran-4.1.2-46.el5_4.1.i386 from installed has depsolving problems --> Missing Dependency: gcc = 4.1.2-46.el5_4.1 is needed by package gcc-gfortran-4.1.2-46.el5_4.1.i386 (installed) cyrus-sasl-devel-2.1.22-5.el5.i386 from installed has depsolving problems --> Missing Dependency: cyrus-sasl-lib = 2.1.22-5.el5 is needed by package cyrus-sasl-devel-2.1.22-5.el5.i386 (installed) rpm-devel-4.4.2.3-18.el5.i386 from installed has depsolving problems --> Missing Dependency: popt = 1.10.2.3-18.el5 is needed by package rpm-devel-4.4.2.3-18.el5.i386 (installed) db4-devel-4.3.29-10.el5.i386 from installed has depsolving problems --> Missing Dependency: db4 = 4.3.29-10.el5 is needed by package db4-devel-4.3.29-10.el5.i386 (installed) rpm-build-4.4.2.3-18.el5.i386 from installed has depsolving problems --> Missing Dependency: popt = 1.10.2.3-18.el5 is needed by package rpm-build-4.4.2.3-18.el5.i386 (installed) rpm-devel-4.4.2.3-18.el5.i386 from installed has depsolving problems --> Missing Dependency: rpm = 4.4.2.3-18.el5 is needed by package rpm-devel-4.4.2.3-18.el5.i386 (installed) libXi-devel-1.0.1-3.1.i386 from installed has depsolving problems --> Missing Dependency: libXi = 1.0.1-3.1 is needed by package libXi-devel-1.0.1-3.1.i386 (installed) hal-devel-0.5.8.1-52.el5.i386 from installed has depsolving problems --> Missing Dependency: hal = 0.5.8.1-52.el5 is needed by package hal-devel-0.5.8.1-52.el5.i386 (installed) freetype-devel-2.2.1-21.el5_3.i386 from installed has depsolving problems --> Missing Dependency: freetype = 2.2.1-21.el5_3 is needed by package freetype-devel-2.2.1-21.el5_3.i386 (installed) Error: Missing Dependency: libgfortran = 4.1.2-46.el5_4.1 is needed by package gcc-gfortran-4.1.2-46.el5_4.1.i386 (installed) Error: Missing Dependency: libsepol = 1.15.2-2.el5 is needed by package libsepol-devel-1.15.2-2.el5.i386 (installed) Error: Missing Dependency: libstdc++ = 4.1.2-46.el5_4.1 is needed by package gcc-c++-4.1.2-46.el5_4.1.i386 (installed) Error: Missing Dependency: mesa-libGL = 6.5.1-7.7.el5 is needed by package mesa-libGL-devel-6.5.1-7.7.el5.i386 (installed) Error: Missing Dependency: mesa-libGLU = 6.5.1-7.7.el5 is needed by package mesa-libGLU-devel-6.5.1-7.7.el5.i386 (installed) Error: Missing Dependency: freetype = 2.2.1-21.el5_3 is needed by package freetype-devel-2.2.1-21.el5_3.i386 (installed) Error: Missing Dependency: hal = 0.5.8.1-52.el5 is needed by package hal-devel-0.5.8.1-52.el5.i386 (installed) Error: Missing Dependency: libXt = 1.0.2-3.1.fc6 is needed by package libXt-devel-1.0.2-3.1.fc6.i386 (installed) Error: Missing Dependency: openldap = 2.3.43-3.el5 is needed by package openldap-devel-2.3.43-3.el5.i386 (installed) Error: Missing Dependency: libstdc++ = 4.1.2-46.el5_4.1 is needed by package libstdc++-devel-4.1.2-46.el5_4.1.i386 (installed) Error: Missing Dependency: nss-devel >= 3.12.6 is needed by package xulrunner-devel-1.9.2.7-2.el5.i386 (rhel-i386-client-5) Error: Missing Dependency: newt = 0.52.2-12.el5_4.1 is needed by package newt-devel-0.52.2-12.el5_4.1.i386 (installed) Error: Missing Dependency: gnutls = 1.4.1-3.el5_3.5 is needed by package gnutls-devel-1.4.1-3.el5_3.5.i386 (installed) Error: Missing Dependency: gnome-vfs2 = 2.16.2-4.el5 is needed by package gnome-vfs2-devel-2.16.2-4.el5.i386 (installed) Error: Missing Dependency: libXrandr = 1.1.1-3.1 is needed by package libXrandr-devel-1.1.1-3.1.i386 (installed) Error: Missing Dependency: python = 2.4.3-27.el5 is needed by package python-devel-2.4.3-27.el5.i386 (installed) Error: Missing Dependency: gcc = 4.1.2-46.el5_4.1 is needed by package gcc-c++-4.1.2-46.el5_4.1.i386 (installed) Error: Missing Dependency: libnotify-devel is needed by package xulrunner-devel-1.9.2.7-2.el5.i386 (rhel-i386-client-5) Error: Missing Dependency: popt = 1.10.2.3-18.el5 is needed by package rpm-devel-4.4.2.3-18.el5.i386 (installed) Error: Missing Dependency: openssl = 0.9.8e-12.el5 is needed by package openssl-devel-0.9.8e-12.el5.i386 (installed) Error: Missing Dependency: curl = 7.15.5-2.1.el5_3.5 is needed by package curl-devel-7.15.5-2.1.el5_3.5.i386 (installed) Error: Missing Dependency: xulrunner = 1.9.2.7-2.el5 is needed by package xulrunner-devel-1.9.2.7-2.el5.i386 (rhel-i386-client-5) Error: Missing Dependency: nspr = 4.7.6-1.el5_4 is needed by package nspr-devel-4.7.6-1.el5_4.i386 (installed) Error: Missing Dependency: nss = 3.12.3.99.3-1.el5_3.2 is needed by package nss-devel-3.12.3.99.3-1.el5_3.2.i386 (installed) Error: Missing Dependency: popt = 1.10.2.3-18.el5 is needed by package rpm-build-4.4.2.3-18.el5.i386 (installed) Error: Missing Dependency: libXi = 1.0.1-3.1 is needed by package libXi-devel-1.0.1-3.1.i386 (installed) Error: Missing Dependency: nspr-devel >= 4.8 is needed by package xulrunner-devel-1.9.2.7-2.el5.i386 (rhel-i386-client-5) Error: Missing Dependency: pam = 0.99.6.2-6.el5 is needed by package pam-devel-0.99.6.2-6.el5.i386 (installed) Error: Missing Dependency: rpm = 4.4.2.3-18.el5 is needed by package rpm-build-4.4.2.3-18.el5.i386 (installed) Error: Missing Dependency: cyrus-sasl-lib = 2.1.22-5.el5 is needed by package cyrus-sasl-devel-2.1.22-5.el5.i386 (installed) Error: Missing Dependency: gtk2 = 2.10.4-20.el5 is needed by package gtk2-devel-2.10.4-20.el5.i386 (installed) Error: Missing Dependency: dbus = 1.1.2-12.el5 is needed by package dbus-devel-1.1.2-12.el5.i386 (installed) Error: Missing Dependency: db4 = 4.3.29-10.el5 is needed by package db4-devel-4.3.29-10.el5.i386 (installed) Error: Missing Dependency: rpm-libs = 4.4.2.3-18.el5 is needed by package rpm-build-4.4.2.3-18.el5.i386 (installed) Error: Missing Dependency: gcc = 4.1.2-46.el5_4.1 is needed by package gcc-gfortran-4.1.2-46.el5_4.1.i386 (installed) Error: Missing Dependency: expat = 1.95.8-8.2.1 is needed by package expat-devel-1.95.8-8.2.1.i386 (installed) Error: Missing Dependency: gd = 2.0.33-9.4.el5_1.1 is needed by package gd-devel-2.0.33-9.4.el5_1.1.i386 (installed) Error: Missing Dependency: krb5-libs = 1.6.1-36.el5 is needed by package krb5-devel-1.6.1-36.el5.i386 (installed) Error: Missing Dependency: rpm = 4.4.2.3-18.el5 is needed by package rpm-devel-4.4.2.3-18.el5.i386 (installed) Error: Missing Dependency: rpm-libs = 4.4.2.3-18.el5 is needed by package rpm-devel-4.4.2.3-18.el5.i386 (installed) Error: Missing Dependency: e2fsprogs-libs = 1.39-23.el5 is needed by package e2fsprogs-devel-1.39-23.el5.i386 (installed) You could try using --skip-broken to work around the problem You could try running: package-cleanup --problems package-cleanup --dupes rpm -Va --nofiles --nodigest The repolist is yum repolist all Loaded plugins: rhnplugin, security repo id repo name status rhel-debuginfo Red Hat Enterprise Linux 5Client - i386 - Deb disabled rhel-debuginfo-beta Red Hat Enterprise Linux 5Client Beta - i386 disabled rhel-i386-client-5 Red Hat Enterprise Linux Desktop (v. 5 for 32 enabled: 6,607 repolist: 6,607

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  • update jframe in java or revalidate/repaint/ panel

    - by user1516251
    How to update a java frame with changed content I want to update a frame or just the panel with updated content. What do I use for this Here is where i want to revalidate the frame or repaint mainpanel or whatever will work I have tried a number of things, but none of them have worked. public void actionPerformed(ActionEvent e) { //System.out.println(e.getActionCommand()); if (e.getActionCommand().equals("advance")) { multi--; // Revalidate update repaint here <<<<<<<<<<<<<<<<<<< } else if (e.getActionCommand().equals("reverse")) { multi++; // Revalidate update repaint here <<<<<<<<<<<<<<<<<<< } else { openURL(e.getActionCommand()); } } Here is the whole java file /* * * */ package build; import java.lang.reflect.Method; import javax.swing.JOptionPane; import java.util.Arrays; import java.util.*; import java.util.ArrayList; import javax.swing.*; import javax.swing.AbstractButton; import javax.swing.JScrollPane; import javax.swing.JButton; import javax.swing.JPanel; import javax.swing.JFrame; import javax.swing.ImageIcon; import java.awt.*; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.KeyEvent; /* * ButtonDemo.java requires the following files: * images/right.gif * images/middle.gif * images/left.gif */ public class StockTable extends JPanel implements ActionListener { static int multi = 1; int roll = 0; static TextVars textvars = new TextVars(); static final String[] browsers = { "firefox", "opera", "konqueror", "epiphany", "seamonkey", "galeon", "kazehakase", "mozilla", "netscape" }; JFrame frame; JPanel mainpanel, panel1, panel2, panel3, panel4, panel2left, panel2center, panel2right; JButton stknames_btn[] = new JButton[textvars.getNumberOfStocks()]; JLabel label[] = new JLabel[textvars.getNumberOfStocks()]; JLabel headlabel, dayspan, namelabel; JRadioButton radioButton; JButton button; JScrollPane scrollpane; int wid = 825; public JPanel createContentPane() { mainpanel = new JPanel(); mainpanel.setPreferredSize(new Dimension(wid, 800)); mainpanel.setLayout(new GridBagLayout()); GridBagConstraints c = new GridBagConstraints(); panel1 = new JPanel(); panel1.setPreferredSize(new Dimension(wid, 25)); c.gridx = 0; c.gridy = 0; c.insets = new Insets(0,0,0,0); mainpanel.add(panel1, c); // Panel 2------------ panel2 = new JPanel(); panel2.setPreferredSize(new Dimension(wid, 51)); c.gridx = 0; c.gridy = 1; c.insets = new Insets(0,0,0,0); mainpanel.add(panel2, c); panel2left = new JPanel(); panel2left.setPreferredSize(new Dimension(270, 51)); c.gridx = 0; c.gridy = 1; c.insets = new Insets(0,0,0,0); panel2.add(panel2left, c); panel2center = new JPanel(); panel2center.setPreferredSize(new Dimension(258, 51)); c.gridx = 1; c.gridy = 1; c.insets = new Insets(0,0,0,0); panel2.add(panel2center, c); panel2right = new JPanel(); panel2right.setPreferredSize(new Dimension(270, 51)); c.gridx = 2; c.gridy = 1; c.insets = new Insets(0,0,0,0); panel2.add(panel2right, c); // ------------------ panel3 = new JPanel(); panel3.setLayout(new GridBagLayout()); scrollpane = new JScrollPane(panel3); scrollpane.setPreferredSize(new Dimension(wid, 675)); c.gridx = 0; c.gridy = 2; c.insets = new Insets(0,0,0,0); mainpanel.add(scrollpane, c); ImageIcon leftButtonIcon = createImageIcon("images/right.gif"); //b1 = new JButton("Disable middle button", leftButtonIcon); //b1.setVerticalTextPosition(AbstractButton.CENTER); //b1.setHorizontalTextPosition(AbstractButton.LEADING); //aka LEFT, for left-to-right locales //b1.setMnemonic(KeyEvent.VK_D); //b1.setActionCommand("disable"); //Listen for actions on buttons 1 //b1.addActionListener(this); //b1.setToolTipText("Click this button to disable the middle button."); //Add Components to this container, using the default FlowLayout. //add(b1); headlabel = new JLabel("hellorow1"); c.gridx = 0; c.gridy = 0; c.insets = new Insets(0, 0, 0, 0); panel1.add(headlabel, c); radioButton = new JRadioButton("Percentage"); c.gridx = 2; c.gridy = 0; c.insets = new Insets(0, 0, 0, 0); panel1.add(radioButton, c); radioButton = new JRadioButton("Days Range"); c.gridx = 3; c.gridy = 0; c.insets = new Insets(0, 0, 0, 0); panel1.add(radioButton, c); radioButton = new JRadioButton("Open / Close"); c.gridx = 4; c.gridy = 0; c.insets = new Insets(0, 0, 0,0 ); panel1.add(radioButton, c); button = new JButton("<<"); button.setPreferredSize(new Dimension(50, 50)); button.setActionCommand("reverse"); button.addActionListener(this); c.gridx = 0; c.gridy = 1; c.insets = new Insets(0, 0, 0, 0); panel2left.add(button, c); dayspan = new JLabel("hellorow2"); dayspan.setHorizontalAlignment(JLabel.CENTER); dayspan.setVerticalAlignment(JLabel.CENTER); dayspan.setPreferredSize(new Dimension(270, 50)); c.gridx = 1; c.gridy = 1; c.insets = new Insets(0, 0, 0, 0); panel2center.add(dayspan, c); button = new JButton(">>"); button.setPreferredSize(new Dimension(50, 50)); button.setActionCommand("advance"); button.addActionListener(this); if (multi == 0) { button.setEnabled(false); } else { button.setEnabled(true); } c.gridx = 2; c.gridy = 1; c.insets = new Insets(0, 0, 0, 0); panel2right.add(button, c); int availSpace_int = textvars.getStocks().size()-textvars.getNumberOfStocks()*7; ArrayList<String[]> stocknames = textvars.getStockNames(); ArrayList<String[]> stocks = textvars.getStocks(); for (int column = 0; column < 8; column++) { for (int row = 0; row < textvars.getNumberOfStocks(); row++) { if (column==0) { if (row==0) { namelabel = new JLabel(stocknames.get(0)[0]); namelabel.setVerticalAlignment(JLabel.CENTER); namelabel.setHorizontalAlignment(JLabel.CENTER); namelabel.setPreferredSize(new Dimension(100, 25)); c.gridx = column; c.gridy = row; c.insets = new Insets(0, 0, 0, 0); panel3.add(namelabel, c); } else { stknames_btn[row] = new JButton(stocknames.get(row)[0], leftButtonIcon); stknames_btn[row].setVerticalTextPosition(AbstractButton.CENTER); stknames_btn[row].setActionCommand(stocknames.get(row)[1]); stknames_btn[row].addActionListener(this); stknames_btn[row].setToolTipText("go to Google Finance "+stocknames.get(row)[0]); stknames_btn[row].setPreferredSize(new Dimension(100, 25)); c.gridx = column; c.gridy = row; c.insets = new Insets(0, 0, 0, 0); //scrollpane.add(stknames[row], c); panel3.add(stknames_btn[row], c); } } else { label[row]= new JLabel(textvars.getStocks().get(columnMulti(multi))[1]); label[row].setBorder(BorderFactory.createLineBorder(Color.black)); label[row].setVerticalAlignment(JLabel.CENTER); label[row].setHorizontalAlignment(JLabel.CENTER); label[row].setPreferredSize(new Dimension(100, 25)); c.gridx = column; c.gridy = row; c.insets = new Insets(0,0,0,0); panel3.add(label[row], c); } } } return mainpanel; } public void actionPerformed(ActionEvent e) { //System.out.println(e.getActionCommand()); if (e.getActionCommand().equals("advance")) { multi--; } else if (e.getActionCommand().equals("reverse")) { multi++; } else { openURL(e.getActionCommand()); } } /** Returns an ImageIcon, or null if the path was invalid. */ protected static ImageIcon createImageIcon(String path) { java.net.URL imgURL = StockTable.class.getResource(path); if (imgURL != null) { return new ImageIcon(imgURL); } else { System.err.println("Couldn't find file: " + path); return null; } } public static void openURL(String url) { String osName = System.getProperty("os.name"); try { if (osName.startsWith("Mac OS")) { Class<?> fileMgr = Class.forName("com.apple.eio.FileManager"); Method openURL = fileMgr.getDeclaredMethod("openURL", new Class[] {String.class}); openURL.invoke(null, new Object[] {url}); } else if (osName.startsWith("Windows")) { Runtime.getRuntime().exec("rundll32 url.dll,FileProtocolHandler " + url); } else { //assume Unix or Linux boolean found = false; for (String browser : browsers) if (!found) { found = Runtime.getRuntime().exec( new String[] {"which", browser}).waitFor() == 0; if (found) Runtime.getRuntime().exec(new String[] {browser, url}); } if (!found) throw new Exception(Arrays.toString(browsers)); } } catch (Exception e) { JOptionPane.showMessageDialog(null, "Error attempting to launch web browser\n" + e.toString()); } } int reit = 0; int start = textvars.getStocks().size()-((textvars.getNumberOfStocks()*5)*7)-1; public int columnMulti(int multi) { reit++; start++; if (reit == textvars.getNumberOfStocks()) { reit = 0; start=start+64; } //start = start - (multi*(textvars.getNumberOfStocks())); return start; } /** * Create the GUI and show it. For thread safety, * this method should be invoked from the * event-dispatching thread. */ private static void createAndShowGUI() { //Create and set up the window. JFrame frame = new JFrame("Stock Table"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Create and set up the content pane. StockTable newContentPane = new StockTable(); //newContentPane.setOpaque(true); //content panes must be opaque //frame.setContentPane(newContentPane); frame.setContentPane(newContentPane.createContentPane()); frame.setSize(800, 800); //Display the window. frame.pack(); frame.setVisible(true); } public static void main(String[] args) { //Schedule a job for the event-dispatching thread: //creating and showing this application's GUI. javax.swing.SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGUI(); } }); } }

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  • Agile Development

    - by James Oloo Onyango
    Alot of literature has and is being written about agile developement and its surrounding philosophies. In my quest to find the best way to express the importance of agile methodologies, i have found Robert C. Martin's "A Satire Of Two Companies" to be both the most concise and thorough! Enjoy the read! Rufus Inc Project Kick Off Your name is Bob. The date is January 3, 2001, and your head still aches from the recent millennial revelry. You are sitting in a conference room with several managers and a group of your peers. You are a project team leader. Your boss is there, and he has brought along all of his team leaders. His boss called the meeting. "We have a new project to develop," says your boss's boss. Call him BB. The points in his hair are so long that they scrape the ceiling. Your boss's points are just starting to grow, but he eagerly awaits the day when he can leave Brylcream stains on the acoustic tiles. BB describes the essence of the new market they have identified and the product they want to develop to exploit this market. "We must have this new project up and working by fourth quarter October 1," BB demands. "Nothing is of higher priority, so we are cancelling your current project." The reaction in the room is stunned silence. Months of work are simply going to be thrown away. Slowly, a murmur of objection begins to circulate around the conference table.   His points give off an evil green glow as BB meets the eyes of everyone in the room. One by one, that insidious stare reduces each attendee to quivering lumps of protoplasm. It is clear that he will brook no discussion on this matter. Once silence has been restored, BB says, "We need to begin immediately. How long will it take you to do the analysis?" You raise your hand. Your boss tries to stop you, but his spitwad misses you and you are unaware of his efforts.   "Sir, we can't tell you how long the analysis will take until we have some requirements." "The requirements document won't be ready for 3 or 4 weeks," BB says, his points vibrating with frustration. "So, pretend that you have the requirements in front of you now. How long will you require for analysis?" No one breathes. Everyone looks around to see whether anyone has some idea. "If analysis goes beyond April 1, we have a problem. Can you finish the analysis by then?" Your boss visibly gathers his courage: "We'll find a way, sir!" His points grow 3 mm, and your headache increases by two Tylenol. "Good." BB smiles. "Now, how long will it take to do the design?" "Sir," you say. Your boss visibly pales. He is clearly worried that his 3 mms are at risk. "Without an analysis, it will not be possible to tell you how long design will take." BB's expression shifts beyond austere.   "PRETEND you have the analysis already!" he says, while fixing you with his vacant, beady little eyes. "How long will it take you to do the design?" Two Tylenol are not going to cut it. Your boss, in a desperate attempt to save his new growth, babbles: "Well, sir, with only six months left to complete the project, design had better take no longer than 3 months."   "I'm glad you agree, Smithers!" BB says, beaming. Your boss relaxes. He knows his points are secure. After a while, he starts lightly humming the Brylcream jingle. BB continues, "So, analysis will be complete by April 1, design will be complete by July 1, and that gives you 3 months to implement the project. This meeting is an example of how well our new consensus and empowerment policies are working. Now, get out there and start working. I'll expect to see TQM plans and QIT assignments on my desk by next week. Oh, and don't forget that your crossfunctional team meetings and reports will be needed for next month's quality audit." "Forget the Tylenol," you think to yourself as you return to your cubicle. "I need bourbon."   Visibly excited, your boss comes over to you and says, "Gosh, what a great meeting. I think we're really going to do some world shaking with this project." You nod in agreement, too disgusted to do anything else. "Oh," your boss continues, "I almost forgot." He hands you a 30-page document. "Remember that the SEI is coming to do an evaluation next week. This is the evaluation guide. You need to read through it, memorize it, and then shred it. It tells you how to answer any questions that the SEI auditors ask you. It also tells you what parts of the building you are allowed to take them to and what parts to avoid. We are determined to be a CMM level 3 organization by June!"   You and your peers start working on the analysis of the new project. This is difficult because you have no requirements. But from the 10-minute introduction given by BB on that fateful morning, you have some idea of what the product is supposed to do.   Corporate process demands that you begin by creating a use case document. You and your team begin enumerating use cases and drawing oval and stick diagrams. Philosophical debates break out among the team members. There is disagreement as to whether certain use cases should be connected with <<extends>> or <<includes>> relationships. Competing models are created, but nobody knows how to evaluate them. The debate continues, effectively paralyzing progress.   After a week, somebody finds the iceberg.com Web site, which recommends disposing entirely of <<extends>> and <<includes>> and replacing them with <<precedes>> and <<uses>>. The documents on this Web site, authored by Don Sengroiux, describes a method known as stalwart-analysis, which claims to be a step-by-step method for translating use cases into design diagrams. More competing use case models are created using this new scheme, but again, people can't agree on how to evaluate them. The thrashing continues. More and more, the use case meetings are driven by emotion rather than by reason. If it weren't for the fact that you don't have requirements, you'd be pretty upset by the lack of progress you are making. The requirements document arrives on February 15. And then again on February 20, 25, and every week thereafter. Each new version contradicts the previous one. Clearly, the marketing folks who are writing the requirements, empowered though they might be, are not finding consensus.   At the same time, several new competing use case templates have been proposed by the various team members. Each template presents its own particularly creative way of delaying progress. The debates rage on. On March 1, Prudence Putrigence, the process proctor, succeeds in integrating all the competing use case forms and templates into a single, all-encompassing form. Just the blank form is 15 pages long. She has managed to include every field that appeared on all the competing templates. She also presents a 159- page document describing how to fill out the use case form. All current use cases must be rewritten according to the new standard.   You marvel to yourself that it now requires 15 pages of fill-in-the-blank and essay questions to answer the question: What should the system do when the user presses Return? The corporate process (authored by L. E. Ott, famed author of "Holistic Analysis: A Progressive Dialectic for Software Engineers") insists that you discover all primary use cases, 87 percent of all secondary use cases, and 36.274 percent of all tertiary use cases before you can complete analysis and enter the design phase. You have no idea what a tertiary use case is. So in an attempt to meet this requirement, you try to get your use case document reviewed by the marketing department, which you hope will know what a tertiary use case is.   Unfortunately, the marketing folks are too busy with sales support to talk to you. Indeed, since the project started, you have not been able to get a single meeting with marketing, which has provided a never-ending stream of changing and contradictory requirements documents.   While one team has been spinning endlessly on the use case document, another team has been working out the domain model. Endless variations of UML documents are pouring out of this team. Every week, the model is reworked.   The team members can't decide whether to use <<interfaces>> or <<types>> in the model. A huge disagreement has been raging on the proper syntax and application of OCL. Others on the team just got back from a 5-day class on catabolism, and have been producing incredibly detailed and arcane diagrams that nobody else can fathom.   On March 27, with one week to go before analysis is to be complete, you have produced a sea of documents and diagrams but are no closer to a cogent analysis of the problem than you were on January 3. **** And then, a miracle happens.   **** On Saturday, April 1, you check your e-mail from home. You see a memo from your boss to BB. It states unequivocally that you are done with the analysis! You phone your boss and complain. "How could you have told BB that we were done with the analysis?" "Have you looked at a calendar lately?" he responds. "It's April 1!" The irony of that date does not escape you. "But we have so much more to think about. So much more to analyze! We haven't even decided whether to use <<extends>> or <<precedes>>!" "Where is your evidence that you are not done?" inquires your boss, impatiently. "Whaaa . . . ." But he cuts you off. "Analysis can go on forever; it has to be stopped at some point. And since this is the date it was scheduled to stop, it has been stopped. Now, on Monday, I want you to gather up all existing analysis materials and put them into a public folder. Release that folder to Prudence so that she can log it in the CM system by Monday afternoon. Then get busy and start designing."   As you hang up the phone, you begin to consider the benefits of keeping a bottle of bourbon in your bottom desk drawer. They threw a party to celebrate the on-time completion of the analysis phase. BB gave a colon-stirring speech on empowerment. And your boss, another 3 mm taller, congratulated his team on the incredible show of unity and teamwork. Finally, the CIO takes the stage to tell everyone that the SEI audit went very well and to thank everyone for studying and shredding the evaluation guides that were passed out. Level 3 now seems assured and will be awarded by June. (Scuttlebutt has it that managers at the level of BB and above are to receive significant bonuses once the SEI awards level 3.)   As the weeks flow by, you and your team work on the design of the system. Of course, you find that the analysis that the design is supposedly based on is flawedno, useless; no, worse than useless. But when you tell your boss that you need to go back and work some more on the analysis to shore up its weaker sections, he simply states, "The analysis phase is over. The only allowable activity is design. Now get back to it."   So, you and your team hack the design as best you can, unsure of whether the requirements have been properly analyzed. Of course, it really doesn't matter much, since the requirements document is still thrashing with weekly revisions, and the marketing department still refuses to meet with you.     The design is a nightmare. Your boss recently misread a book named The Finish Line in which the author, Mark DeThomaso, blithely suggested that design documents should be taken down to code-level detail. "If we are going to be working at that level of detail," you ask, "why don't we simply write the code instead?" "Because then you wouldn't be designing, of course. And the only allowable activity in the design phase is design!" "Besides," he continues, "we have just purchased a companywide license for Dandelion! This tool enables 'Round the Horn Engineering!' You are to transfer all design diagrams into this tool. It will automatically generate our code for us! It will also keep the design diagrams in sync with the code!" Your boss hands you a brightly colored shrinkwrapped box containing the Dandelion distribution. You accept it numbly and shuffle off to your cubicle. Twelve hours, eight crashes, one disk reformatting, and eight shots of 151 later, you finally have the tool installed on your server. You consider the week your team will lose while attending Dandelion training. Then you smile and think, "Any week I'm not here is a good week." Design diagram after design diagram is created by your team. Dandelion makes it very difficult to draw these diagrams. There are dozens and dozens of deeply nested dialog boxes with funny text fields and check boxes that must all be filled in correctly. And then there's the problem of moving classes between packages. At first, these diagram are driven from the use cases. But the requirements are changing so often that the use cases rapidly become meaningless. Debates rage about whether VISITOR or DECORATOR design patterns should be used. One developer refuses to use VISITOR in any form, claiming that it's not a properly object-oriented construct. Someone refuses to use multiple inheritance, since it is the spawn of the devil. Review meetings rapidly degenerate into debates about the meaning of object orientation, the definition of analysis versus design, or when to use aggregation versus association. Midway through the design cycle, the marketing folks announce that they have rethought the focus of the system. Their new requirements document is completely restructured. They have eliminated several major feature areas and replaced them with feature areas that they anticipate customer surveys will show to be more appropriate. You tell your boss that these changes mean that you need to reanalyze and redesign much of the system. But he says, "The analysis phase is system. But he says, "The analysis phase is over. The only allowable activity is design. Now get back to it."   You suggest that it might be better to create a simple prototype to show to the marketing folks and even some potential customers. But your boss says, "The analysis phase is over. The only allowable activity is design. Now get back to it." Hack, hack, hack, hack. You try to create some kind of a design document that might reflect the new requirements documents. However, the revolution of the requirements has not caused them to stop thrashing. Indeed, if anything, the wild oscillations of the requirements document have only increased in frequency and amplitude.   You slog your way through them.   On June 15, the Dandelion database gets corrupted. Apparently, the corruption has been progressive. Small errors in the DB accumulated over the months into bigger and bigger errors. Eventually, the CASE tool just stopped working. Of course, the slowly encroaching corruption is present on all the backups. Calls to the Dandelion technical support line go unanswered for several days. Finally, you receive a brief e-mail from Dandelion, informing you that this is a known problem and that the solution is to purchase the new version, which they promise will be ready some time next quarter, and then reenter all the diagrams by hand.   ****   Then, on July 1 another miracle happens! You are done with the design!   Rather than go to your boss and complain, you stock your middle desk drawer with some vodka.   **** They threw a party to celebrate the on-time completion of the design phase and their graduation to CMM level 3. This time, you find BB's speech so stirring that you have to use the restroom before it begins. New banners and plaques are all over your workplace. They show pictures of eagles and mountain climbers, and they talk about teamwork and empowerment. They read better after a few scotches. That reminds you that you need to clear out your file cabinet to make room for the brandy. You and your team begin to code. But you rapidly discover that the design is lacking in some significant areas. Actually, it's lacking any significance at all. You convene a design session in one of the conference rooms to try to work through some of the nastier problems. But your boss catches you at it and disbands the meeting, saying, "The design phase is over. The only allowable activity is coding. Now get back to it."   ****   The code generated by Dandelion is really hideous. It turns out that you and your team were using association and aggregation the wrong way, after all. All the generated code has to be edited to correct these flaws. Editing this code is extremely difficult because it has been instrumented with ugly comment blocks that have special syntax that Dandelion needs in order to keep the diagrams in sync with the code. If you accidentally alter one of these comments, the diagrams will be regenerated incorrectly. It turns out that "Round the Horn Engineering" requires an awful lot of effort. The more you try to keep the code compatible with Dandelion, the more errors Dandelion generates. In the end, you give up and decide to keep the diagrams up to date manually. A second later, you decide that there's no point in keeping the diagrams up to date at all. Besides, who has time?   Your boss hires a consultant to build tools to count the number of lines of code that are being produced. He puts a big thermometer graph on the wall with the number 1,000,000 on the top. Every day, he extends the red line to show how many lines have been added. Three days after the thermometer appears on the wall, your boss stops you in the hall. "That graph isn't growing quickly enough. We need to have a million lines done by October 1." "We aren't even sh-sh-sure that the proshect will require a m-million linezh," you blather. "We have to have a million lines done by October 1," your boss reiterates. His points have grown again, and the Grecian formula he uses on them creates an aura of authority and competence. "Are you sure your comment blocks are big enough?" Then, in a flash of managerial insight, he says, "I have it! I want you to institute a new policy among the engineers. No line of code is to be longer than 20 characters. Any such line must be split into two or more preferably more. All existing code needs to be reworked to this standard. That'll get our line count up!"   You decide not to tell him that this will require two unscheduled work months. You decide not to tell him anything at all. You decide that intravenous injections of pure ethanol are the only solution. You make the appropriate arrangements. Hack, hack, hack, and hack. You and your team madly code away. By August 1, your boss, frowning at the thermometer on the wall, institutes a mandatory 50-hour workweek.   Hack, hack, hack, and hack. By September 1st, the thermometer is at 1.2 million lines and your boss asks you to write a report describing why you exceeded the coding budget by 20 percent. He institutes mandatory Saturdays and demands that the project be brought back down to a million lines. You start a campaign of remerging lines. Hack, hack, hack, and hack. Tempers are flaring; people are quitting; QA is raining trouble reports down on you. Customers are demanding installation and user manuals; salespeople are demanding advance demonstrations for special customers; the requirements document is still thrashing, the marketing folks are complaining that the product isn't anything like they specified, and the liquor store won't accept your credit card anymore. Something has to give.    On September 15, BB calls a meeting. As he enters the room, his points are emitting clouds of steam. When he speaks, the bass overtones of his carefully manicured voice cause the pit of your stomach to roll over. "The QA manager has told me that this project has less than 50 percent of the required features implemented. He has also informed me that the system crashes all the time, yields wrong results, and is hideously slow. He has also complained that he cannot keep up with the continuous train of daily releases, each more buggy than the last!" He stops for a few seconds, visibly trying to compose himself. "The QA manager estimates that, at this rate of development, we won't be able to ship the product until December!" Actually, you think it's more like March, but you don't say anything. "December!" BB roars with such derision that people duck their heads as though he were pointing an assault rifle at them. "December is absolutely out of the question. Team leaders, I want new estimates on my desk in the morning. I am hereby mandating 65-hour work weeks until this project is complete. And it better be complete by November 1."   As he leaves the conference room, he is heard to mutter: "Empowermentbah!" * * * Your boss is bald; his points are mounted on BB's wall. The fluorescent lights reflecting off his pate momentarily dazzle you. "Do you have anything to drink?" he asks. Having just finished your last bottle of Boone's Farm, you pull a bottle of Thunderbird from your bookshelf and pour it into his coffee mug. "What's it going to take to get this project done? " he asks. "We need to freeze the requirements, analyze them, design them, and then implement them," you say callously. "By November 1?" your boss exclaims incredulously. "No way! Just get back to coding the damned thing." He storms out, scratching his vacant head.   A few days later, you find that your boss has been transferred to the corporate research division. Turnover has skyrocketed. Customers, informed at the last minute that their orders cannot be fulfilled on time, have begun to cancel their orders. Marketing is re-evaluating whether this product aligns with the overall goals of the company. Memos fly, heads roll, policies change, and things are, overall, pretty grim. Finally, by March, after far too many sixty-five hour weeks, a very shaky version of the software is ready. In the field, bug-discovery rates are high, and the technical support staff are at their wits' end, trying to cope with the complaints and demands of the irate customers. Nobody is happy.   In April, BB decides to buy his way out of the problem by licensing a product produced by Rupert Industries and redistributing it. The customers are mollified, the marketing folks are smug, and you are laid off.     Rupert Industries: Project Alpha   Your name is Robert. The date is January 3, 2001. The quiet hours spent with your family this holiday have left you refreshed and ready for work. You are sitting in a conference room with your team of professionals. The manager of the division called the meeting. "We have some ideas for a new project," says the division manager. Call him Russ. He is a high-strung British chap with more energy than a fusion reactor. He is ambitious and driven but understands the value of a team. Russ describes the essence of the new market opportunity the company has identified and introduces you to Jane, the marketing manager, who is responsible for defining the products that will address it. Addressing you, Jane says, "We'd like to start defining our first product offering as soon as possible. When can you and your team meet with me?" You reply, "We'll be done with the current iteration of our project this Friday. We can spare a few hours for you between now and then. After that, we'll take a few people from the team and dedicate them to you. We'll begin hiring their replacements and the new people for your team immediately." "Great," says Russ, "but I want you to understand that it is critical that we have something to exhibit at the trade show coming up this July. If we can't be there with something significant, we'll lose the opportunity."   "I understand," you reply. "I don't yet know what it is that you have in mind, but I'm sure we can have something by July. I just can't tell you what that something will be right now. In any case, you and Jane are going to have complete control over what we developers do, so you can rest assured that by July, you'll have the most important things that can be accomplished in that time ready to exhibit."   Russ nods in satisfaction. He knows how this works. Your team has always kept him advised and allowed him to steer their development. He has the utmost confidence that your team will work on the most important things first and will produce a high-quality product.   * * *   "So, Robert," says Jane at their first meeting, "How does your team feel about being split up?" "We'll miss working with each other," you answer, "but some of us were getting pretty tired of that last project and are looking forward to a change. So, what are you people cooking up?" Jane beams. "You know how much trouble our customers currently have . . ." And she spends a half hour or so describing the problem and possible solution. "OK, wait a second" you respond. "I need to be clear about this." And so you and Jane talk about how this system might work. Some of her ideas aren't fully formed. You suggest possible solutions. She likes some of them. You continue discussing.   During the discussion, as each new topic is addressed, Jane writes user story cards. Each card represents something that the new system has to do. The cards accumulate on the table and are spread out in front of you. Both you and Jane point at them, pick them up, and make notes on them as you discuss the stories. The cards are powerful mnemonic devices that you can use to represent complex ideas that are barely formed.   At the end of the meeting, you say, "OK, I've got a general idea of what you want. I'm going to talk to the team about it. I imagine they'll want to run some experiments with various database structures and presentation formats. Next time we meet, it'll be as a group, and we'll start identifying the most important features of the system."   A week later, your nascent team meets with Jane. They spread the existing user story cards out on the table and begin to get into some of the details of the system. The meeting is very dynamic. Jane presents the stories in the order of their importance. There is much discussion about each one. The developers are concerned about keeping the stories small enough to estimate and test. So they continually ask Jane to split one story into several smaller stories. Jane is concerned that each story have a clear business value and priority, so as she splits them, she makes sure that this stays true.   The stories accumulate on the table. Jane writes them, but the developers make notes on them as needed. Nobody tries to capture everything that is said; the cards are not meant to capture everything but are simply reminders of the conversation.   As the developers become more comfortable with the stories, they begin writing estimates on them. These estimates are crude and budgetary, but they give Jane an idea of what the story will cost.   At the end of the meeting, it is clear that many more stories could be discussed. It is also clear that the most important stories have been addressed and that they represent several months worth of work. Jane closes the meeting by taking the cards with her and promising to have a proposal for the first release in the morning.   * * *   The next morning, you reconvene the meeting. Jane chooses five cards and places them on the table. "According to your estimates, these cards represent about one perfect team-week's worth of work. The last iteration of the previous project managed to get one perfect team-week done in 3 real weeks. If we can get these five stories done in 3 weeks, we'll be able to demonstrate them to Russ. That will make him feel very comfortable about our progress." Jane is pushing it. The sheepish look on her face lets you know that she knows it too. You reply, "Jane, this is a new team, working on a new project. It's a bit presumptuous to expect that our velocity will be the same as the previous team's. However, I met with the team yesterday afternoon, and we all agreed that our initial velocity should, in fact, be set to one perfectweek for every 3 real-weeks. So you've lucked out on this one." "Just remember," you continue, "that the story estimates and the story velocity are very tentative at this point. We'll learn more when we plan the iteration and even more when we implement it."   Jane looks over her glasses at you as if to say "Who's the boss around here, anyway?" and then smiles and says, "Yeah, don't worry. I know the drill by now."Jane then puts 15 more cards on the table. She says, "If we can get all these cards done by the end of March, we can turn the system over to our beta test customers. And we'll get good feedback from them."   You reply, "OK, so we've got our first iteration defined, and we have the stories for the next three iterations after that. These four iterations will make our first release."   "So," says Jane, can you really do these five stories in the next 3 weeks?" "I don't know for sure, Jane," you reply. "Let's break them down into tasks and see what we get."   So Jane, you, and your team spend the next several hours taking each of the five stories that Jane chose for the first iteration and breaking them down into small tasks. The developers quickly realize that some of the tasks can be shared between stories and that other tasks have commonalities that can probably be taken advantage of. It is clear that potential designs are popping into the developers' heads. From time to time, they form little discussion knots and scribble UML diagrams on some cards.   Soon, the whiteboard is filled with the tasks that, once completed, will implement the five stories for this iteration. You start the sign-up process by saying, "OK, let's sign up for these tasks." "I'll take the initial database generation." Says Pete. "That's what I did on the last project, and this doesn't look very different. I estimate it at two of my perfect workdays." "OK, well, then, I'll take the login screen," says Joe. "Aw, darn," says Elaine, the junior member of the team, "I've never done a GUI, and kinda wanted to try that one."   "Ah, the impatience of youth," Joe says sagely, with a wink in your direction. "You can assist me with it, young Jedi." To Jane: "I think it'll take me about three of my perfect workdays."   One by one, the developers sign up for tasks and estimate them in terms of their own perfect workdays. Both you and Jane know that it is best to let the developers volunteer for tasks than to assign the tasks to them. You also know full well that you daren't challenge any of the developers' estimates. You know these people, and you trust them. You know that they are going to do the very best they can.   The developers know that they can't sign up for more perfect workdays than they finished in the last iteration they worked on. Once each developer has filled his or her schedule for the iteration, they stop signing up for tasks.   Eventually, all the developers have stopped signing up for tasks. But, of course, tasks are still left on the board.   "I was worried that that might happen," you say, "OK, there's only one thing to do, Jane. We've got too much to do in this iteration. What stories or tasks can we remove?" Jane sighs. She knows that this is the only option. Working overtime at the beginning of a project is insane, and projects where she's tried it have not fared well.   So Jane starts to remove the least-important functionality. "Well, we really don't need the login screen just yet. We can simply start the system in the logged-in state." "Rats!" cries Elaine. "I really wanted to do that." "Patience, grasshopper." says Joe. "Those who wait for the bees to leave the hive will not have lips too swollen to relish the honey." Elaine looks confused. Everyone looks confused. "So . . .," Jane continues, "I think we can also do away with . . ." And so, bit by bit, the list of tasks shrinks. Developers who lose a task sign up for one of the remaining ones.   The negotiation is not painless. Several times, Jane exhibits obvious frustration and impatience. Once, when tensions are especially high, Elaine volunteers, "I'll work extra hard to make up some of the missing time." You are about to correct her when, fortunately, Joe looks her in the eye and says, "When once you proceed down the dark path, forever will it dominate your destiny."   In the end, an iteration acceptable to Jane is reached. It's not what Jane wanted. Indeed, it is significantly less. But it's something the team feels that can be achieved in the next 3 weeks.   And, after all, it still addresses the most important things that Jane wanted in the iteration. "So, Jane," you say when things had quieted down a bit, "when can we expect acceptance tests from you?" Jane sighs. This is the other side of the coin. For every story the development team implements,   Jane must supply a suite of acceptance tests that prove that it works. And the team needs these long before the end of the iteration, since they will certainly point out differences in the way Jane and the developers imagine the system's behaviour.   "I'll get you some example test scripts today," Jane promises. "I'll add to them every day after that. You'll have the entire suite by the middle of the iteration."   * * *   The iteration begins on Monday morning with a flurry of Class, Responsibilities, Collaborators sessions. By midmorning, all the developers have assembled into pairs and are rapidly coding away. "And now, my young apprentice," Joe says to Elaine, "you shall learn the mysteries of test-first design!"   "Wow, that sounds pretty rad," Elaine replies. "How do you do it?" Joe beams. It's clear that he has been anticipating this moment. "OK, what does the code do right now?" "Huh?" replied Elaine, "It doesn't do anything at all; there is no code."   "So, consider our task; can you think of something the code should do?" "Sure," Elaine said with youthful assurance, "First, it should connect to the database." "And thereupon, what must needs be required to connecteth the database?" "You sure talk weird," laughed Elaine. "I think we'd have to get the database object from some registry and call the Connect() method. "Ah, astute young wizard. Thou perceives correctly that we requireth an object within which we can cacheth the database object." "Is 'cacheth' really a word?" "It is when I say it! So, what test can we write that we know the database registry should pass?" Elaine sighs. She knows she'll just have to play along. "We should be able to create a database object and pass it to the registry in a Store() method. And then we should be able to pull it out of the registry with a Get() method and make sure it's the same object." "Oh, well said, my prepubescent sprite!" "Hay!" "So, now, let's write a test function that proves your case." "But shouldn't we write the database object and registry object first?" "Ah, you've much to learn, my young impatient one. Just write the test first." "But it won't even compile!" "Are you sure? What if it did?" "Uh . . ." "Just write the test, Elaine. Trust me." And so Joe, Elaine, and all the other developers began to code their tasks, one test case at a time. The room in which they worked was abuzz with the conversations between the pairs. The murmur was punctuated by an occasional high five when a pair managed to finish a task or a difficult test case.   As development proceeded, the developers changed partners once or twice a day. Each developer got to see what all the others were doing, and so knowledge of the code spread generally throughout the team.   Whenever a pair finished something significant whether a whole task or simply an important part of a task they integrated what they had with the rest of the system. Thus, the code base grew daily, and integration difficulties were minimized.   The developers communicated with Jane on a daily basis. They'd go to her whenever they had a question about the functionality of the system or the interpretation of an acceptance test case.   Jane, good as her word, supplied the team with a steady stream of acceptance test scripts. The team read these carefully and thereby gained a much better understanding of what Jane expected the system to do. By the beginning of the second week, there was enough functionality to demonstrate to Jane. She watched eagerly as the demonstration passed test case after test case. "This is really cool," Jane said as the demonstration finally ended. "But this doesn't seem like one-third of the tasks. Is your velocity slower than anticipated?"   You grimace. You'd been waiting for a good time to mention this to Jane but now she was forcing the issue. "Yes, unfortunately, we are going more slowly than we had expected. The new application server we are using is turning out to be a pain to configure. Also, it takes forever to reboot, and we have to reboot it whenever we make even the slightest change to its configuration."   Jane eyes you with suspicion. The stress of last Monday's negotiations had still not entirely dissipated. She says, "And what does this mean to our schedule? We can't slip it again, we just can't. Russ will have a fit! He'll haul us all into the woodshed and ream us some new ones."   You look Jane right in the eyes. There's no pleasant way to give someone news like this. So you just blurt out, "Look, if things keep going like they're going, we're not going to be done with everything by next Friday. Now it's possible that we'll figure out a way to go faster. But, frankly, I wouldn't depend on that. You should start thinking about one or two tasks that could be removed from the iteration without ruining the demonstration for Russ. Come hell or high water, we are going to give that demonstration on Friday, and I don't think you want us to choose which tasks to omit."   "Aw forchrisakes!" Jane barely manages to stifle yelling that last word as she stalks away, shaking her head. Not for the first time, you say to yourself, "Nobody ever promised me project management would be easy." You are pretty sure it won't be the last time, either.   Actually, things went a bit better than you had hoped. The team did, in fact, have to drop one task from the iteration, but Jane had chosen wisely, and the demonstration for Russ went without a hitch. Russ was not impressed with the progress, but neither was he dismayed. He simply said, "This is pretty good. But remember, we have to be able to demonstrate this system at the trade show in July, and at this rate, it doesn't look like you'll have all that much to show." Jane, whose attitude had improved dramatically with the completion of the iteration, responded to Russ by saying, "Russ, this team is working hard, and well. When July comes around, I am confident that we'll have something significant to demonstrate. It won't be everything, and some of it may be smoke and mirrors, but we'll have something."   Painful though the last iteration was, it had calibrated your velocity numbers. The next iteration went much better. Not because your team got more done than in the last iteration but simply because the team didn't have to remove any tasks or stories in the middle of the iteration.   By the start of the fourth iteration, a natural rhythm has been established. Jane, you, and the team know exactly what to expect from one another. The team is running hard, but the pace is sustainable. You are confident that the team can keep up this pace for a year or more.   The number of surprises in the schedule diminishes to near zero; however, the number of surprises in the requirements does not. Jane and Russ frequently look over the growing system and make recommendations or changes to the existing functionality. But all parties realize that these changes take time and must be scheduled. So the changes do not cause anyone's expectations to be violated. In March, there is a major demonstration of the system to the board of directors. The system is very limited and is not yet in a form good enough to take to the trade show, but progress is steady, and the board is reasonably impressed.   The second release goes even more smoothly than the first. By now, the team has figured out a way to automate Jane's acceptance test scripts. The team has also refactored the design of the system to the point that it is really easy to add new features and change old ones. The second release was done by the end of June and was taken to the trade show. It had less in it than Jane and Russ would have liked, but it did demonstrate the most important features of the system. Although customers at the trade show noticed that certain features were missing, they were very impressed overall. You, Russ, and Jane all returned from the trade show with smiles on your faces. You all felt as though this project was a winner.   Indeed, many months later, you are contacted by Rufus Inc. That company had been working on a system like this for its internal operations. Rufus has canceled the development of that system after a death-march project and is negotiating to license your technology for its environment.   Indeed, things are looking up!

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