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• Connection to webservice times out first time

  - by Neo

  My application needs to connect to a web service. The WSDL file given by the client was converted to java using the wsdl2java utility in axis 2-1.5.2. The problem occurs during the first connection to the webservice. It gives me java.net.SocketTimeoutException: Read timed out at jrockit.net.SocketNativeIO.readBytesPinned(Native Method) at jrockit.net.SocketNativeIO.socketRead(SocketNativeIO.java:46) at java.net.SocketInputStream.socketRead0(SocketInputStream.java) at java.net.SocketInputStream.read(SocketInputStream.java:129) at com.sun.net.ssl.internal.ssl.InputRecord.readFully(InputRecord.java:293) at com.sun.net.ssl.internal.ssl.InputRecord.read(InputRecord.java:331) at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:789) at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readDataRecord(SSLSocketImpl.java:747) at com.sun.net.ssl.internal.ssl.AppInputStream.read(AppInputStream.java:75) at java.io.BufferedInputStream.fill(BufferedInputStream.java:218) at java.io.BufferedInputStream.read(BufferedInputStream.java:238) at org.apache.commons.httpclient.HttpParser.readRawLine(HttpParser.java:78) at org.apache.commons.httpclient.HttpParser.readLine(HttpParser.java:106) at org.apache.commons.httpclient.HttpConnection.readLine(HttpConnection.java:1116) at org.apache.commons.httpclient.MultiThreadedHttpConnectionManager$HttpConnectionAdapter.readLine(MultiThreadedHttpConnectionManager.java:1413) at org.apache.commons.httpclient.HttpMethodBase.readStatusLine(HttpMethodBase.java:1974) at org.apache.commons.httpclient.HttpMethodBase.readResponse(HttpMethodBase.java:1735) at org.apache.commons.httpclient.HttpMethodBase.execute(HttpMethodBase.java:1100) at org.apache.commons.httpclient.HttpMethodDirector.executeWithRetry(HttpMethodDirector.java:398) at org.apache.commons.httpclient.HttpMethodDirector.executeMethod(HttpMethodDirector.java:171) at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:397) at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:346) at org.apache.axis2.transport.http.AbstractHTTPSender.executeMethod(AbstractHTTPSender.java:558) at org.apache.axis2.transport.http.HTTPSender.sendViaPost(HTTPSender.java:199) at org.apache.axis2.transport.http.HTTPSender.send(HTTPSender.java:77) at org.apache.axis2.transport.http.CommonsHTTPTransportSender.writeMessageWithCommons(CommonsHTTPTransportSender.java:400) at org.apache.axis2.transport.http.CommonsHTTPTransportSender.invoke(CommonsHTTPTransportSender.java:225) at org.apache.axis2.engine.AxisEngine.send(AxisEngine.java:438) at org.apache.axis2.description.OutInAxisOperationClient.send(OutInAxisOperation.java:402) at org.apache.axis2.description.OutInAxisOperationClient.executeImpl(OutInAxisOperation.java:230) at org.apache.axis2.client.OperationClient.execute(OperationClient.java:166) at com.jmango.webservice.talker.WCFServiceStub.addSaleSupportRequest(WCFServiceStub.java:270) at com.jmango.domain.salessystem.talkerimp.RequestServiceInfoImp.addanewServiceRequest(RequestServiceInfoImp.java:58) at com.jmango.mobilenexus.service.MobileServiceImp.sendQueryforServiceInfo(MobileServiceImp.java:358) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:307) at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149) at org.springframework.remoting.support.RemoteInvocationTraceInterceptor.invoke(RemoteInvocationTraceInterceptor.java:77) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204) at $Proxy8.sendQueryforServiceInfo(Unknown Source) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at com.caucho.hessian.server.HessianSkeleton.invoke(HessianSkeleton.java:180) at com.caucho.hessian.server.HessianSkeleton.invoke(HessianSkeleton.java:110) at org.springframework.remoting.caucho.Hessian2SkeletonInvoker.invoke(Hessian2SkeletonInvoker.java:94) at org.springframework.remoting.caucho.HessianExporter.invoke(HessianExporter.java:142) at org.springframework.remoting.caucho.HessianServiceExporter.handleRequest(HessianServiceExporter.java:70) at org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter.handle(HttpRequestHandlerAdapter.java:50) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:875) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:807) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:571) at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:512) at javax.servlet.http.HttpServlet.service(HttpServlet.java:637) at javax.servlet.http.HttpServlet.service(HttpServlet.java:718) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:111) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298) at org.apache.jk.server.JkCoyoteHandler.invoke(JkCoyoteHandler.java:190) at org.apache.jk.common.HandlerRequest.invoke(HandlerRequest.java:291) at org.apache.jk.common.ChannelSocket.invoke(ChannelSocket.java:776) at org.apache.jk.common.ChannelSocket.processConnection(ChannelSocket.java:705) at org.apache.jk.common.ChannelSocket$SocketConnection.runIt(ChannelSocket.java:899) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:690) at java.lang.Thread.run(Thread.java:619) I tried searching the web for answers though there was one place which mentions it could be the firewall at the webservice end that is blocking, I wasnt able to find a valid solution. Any help will be much appreciated. Running: Apache Tomcat 6.0 Axis2 1.5.2

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• Is this question too hard for a seasoned C++ architect?

  - by Monomer

  Background Information We're looking to hire a seasoned C++ architect (10+years dev, of which at least 6years must be C++ ) for a high frequency trading platform. Job advert says STL, Boost proficiency is a must with preferences to modern uses of C++. The company I work for is a Fortune 500 IB (aka finance industry), it requires passes in all the standard SHL tests (numeric, vocab, spatial etc) before interviews can commence. Everyone on the team was given the task of coming up with one question to ask the candidates during a written/typed test, please note this is the second test provided to the candidates, the first being Advanced IKM C++ test, done in the offices supervised and without internet access. People passing that do the second test. After roughly 70 candidates, my question has been determined to be statistically the worst performing - aka least number of people attempted it, furthermore even less people were able to give meaningful answers. Please note, the second test is not timed, the candidate can literally take as long as they like (we've had one person take roughly 10.5hrs) My question to SO is this, after SHL and IKM adv c++ tests, backed up with at least 6+ years C++ development experience, is it still ok not to be able to even comment about let alone come up with some loose strategy for solving the following question. The Question There is a class C with methods foo, boo, boo_and_foo and foo_and_boo. Each method takes i,j,k and l clock cycles respectively, where i < j, k < i+j and l < i+j. class C { public: int foo() {...} int boo() {...} int boo_and_foo() {...} int foo_and_boo() {...} }; In code one might write: C c; . . int i = c.foo() + c.boo(); But it would be better to have: int i = c.foo_and_boo(); What changes or techniques could one make to the definition of C, that would allow similar syntax of the original usage, but instead have the compiler generate the latter. Note that foo and boo are not commutative. Possible Solution We were basically looking for an expression templates based approach, and were willing to give marks to anyone who had even hinted or used the phrase or related terminology. We got only two people that used the wording, but weren't able to properly describe how they accomplish the task in detail. We use such techniques all over the place, due to the use of various mathematical operators for matrix and vector based calculations, for example to decide when to use IPP or hand woven implementations at compile time for a particular architecture and many other things. The particular area of software development requires microsecond response times. I believe could/should be able to teach a junior such techniques, but given the assumed caliber of candidates I expected a little more. Is this really a difficult question? Should it be removed? Or are we just not seeing the right candidates?

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• Can't obtain reference to EKReminder array retrieved from fetchRemindersMatchingPredicate

  - by Scionwest

  When I create an NSPredicate via EKEventStore predicateForRemindersInCalendars; and pass it to EKEventStore fetchRemindersMatchingPredicate:completion:^ I can loop through the reminders array provided by the completion code block, but when I try to store a reference to the reminders array, or create a copy of the array into a local variable or instance variable, both array's remain empty. The reminders array is never copied to them. This is the method I am using, in the method, I create a predicate, pass it to the event store and then loop through all of the reminders logging their title via NSLog. I can see the reminder titles during runtime thanks to NSLog, but the local arrayOfReminders object is empty. I also try to add each reminder into an instance variable of NSMutableArray, but once I leave the completion code block, the instance variable remains empty. Am I missing something here? Can someone please tell me why I can't grab a reference to all of the reminders for use through-out the app? I am not having any issues at all accessing and storing EKEvents, but for some reason I can't do it with EKReminders. - (void)findAllReminders { NSPredicate *predicate = [self.eventStore predicateForRemindersInCalendars:nil]; __block NSArray *arrayOfReminders = [[NSArray alloc] init]; [self.eventStore fetchRemindersMatchingPredicate:predicate completion:^(NSArray *reminders) { arrayOfReminders = [reminders copy]; //Does not work. for (EKReminder *reminder in reminders) { [self.remindersForTheDay addObject:reminder]; NSLog(@"%@", reminder.title); } }]; //Always = 0; if ([self.remindersForTheDay count]) { NSLog(@"Instance Variable has reminders!"); } //Always = 0; if ([arrayOfReminders count]) { NSLog(@"Local Variable has reminders!"); } } The eventStore getter is where I perform my instantiation and get access to the event store. - (EKEventStore *)eventStore { if (!_eventStore) { _eventStore = [[EKEventStore alloc] init]; //respondsToSelector indicates iOS 6 support. if ([_eventStore respondsToSelector:@selector(requestAccessToEntityType:completion:)]) { //Request access to user calendar [_eventStore requestAccessToEntityType:EKEntityTypeEvent completion:^(BOOL granted, NSError *error) { if (granted) { NSLog(@"iOS 6+ Access to EventStore calendar granted."); } else { NSLog(@"Access to EventStore calendar denied."); } }]; //Request access to user Reminders [_eventStore requestAccessToEntityType:EKEntityTypeReminder completion:^(BOOL granted, NSError *error) { if (granted) { NSLog(@"iOS 6+ Access to EventStore Reminders granted."); } else { NSLog(@"Access to EventStore Reminders denied."); } }]; } else { //iOS 5.x and lower support if Selector is not supported NSLog(@"iOS 5.x < Access to EventStore calendar granted."); } for (EKCalendar *cal in self.calendars) { NSLog(@"Calendar found: %@", cal.title); } [_eventStore reset]; } return _eventStore; } Lastly, just to show that I am initializing my remindersForTheDay instance variable using lazy instantiation. - (NSMutableArray *)remindersForTheDay { if (!_remindersForTheDay) _remindersForTheDay = [[NSMutableArray alloc] init]; return _remindersForTheDay; } I've read through the Apple documentation and it doesn't provide any explanation that I can find to answer this. I read through the Blocks Programming docs and it states that you can access local and instance variables without issues from within a block, but for some reason, the above code does not work. Any help would be greatly appreciated, I've scoured Google for answers but have yet to get this figured out. Thanks everyone! Johnathon.

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• Stored proc running 30% slower through Java versus running directly on database

  - by James B

  Hi All, I'm using Java 1.6, JTDS 1.2.2 (also just tried 1.2.4 to no avail) and SQL Server 2005 to create a CallableStatement to run a stored procedure (with no parameters). I am seeing the Java wrapper running the same stored procedure 30% slower than using SQL Server Management Studio. I've run the MS SQL profiler and there is little difference in I/O between the two processes, so I don't think it's related to query plan caching. The stored proc takes no arguments and returns no data. It uses a server-side cursor to calculate the values that are needed to populate a table. I can't see how the calling a stored proc from Java should add a 30% overhead, surely it's just a pipe to the database that SQL is sent down and then the database executes it....Could the database be giving the Java app a different query plan?? I've posted to both the MSDN forums, and the sourceforge JTDS forums (topic: "stored proc slower in JTDS than direct in DB") I was wondering if anyone has any suggestions as to why this might be happening? Thanks in advance, -James (N.B. Fear not, I will collate any answers I get in other forums together here once I find the solution) Java code snippet: sLogger.info("Preparing call..."); stmt = mCon.prepareCall("SP_WB200_POPULATE_TABLE_limited_rows"); sLogger.info("Call prepared. Executing procedure..."); stmt.executeQuery(); sLogger.info("Procedure complete."); I have run sql profiler, and found the following: Java app : CPU: 466,514 Reads: 142,478,387 Writes: 284,078 Duration: 983,796 SSMS : CPU: 466,973 Reads: 142,440,401 Writes: 280,244 Duration: 769,851 (Both with DBCC DROPCLEANBUFFERS run prior to profiling, and both produce the correct number of rows) So my conclusion is that they both execute the same reads and writes, it's just that the way they are doing it is different, what do you guys think? It turns out that the query plans are significantly different for the different clients (the Java client is updating an index during an insert that isn't in the faster SQL client, also, the way it is executing joins is different (nested loops Vs. gather streams, nested loops Vs index scans, argh!)). Quite why this is, I don't know yet (I'll re-post when I do get to the bottom of it) Epilogue I couldn't get this to work properly. I tried homogenising the connection properties (arithabort, ansi_nulls etc) between the Java and Mgmt studio clients. It ended up the two different clients had very similar query/execution plans (but still with different actual plan_ids). I posted a summary of what I found to the MSDN SQL Server forums as I found differing performance not just between a JDBC client and management studio, but also between Microsoft's own command line client, SQLCMD, I also checked some more radical things like network traffic too, or wrapping the stored proc inside another stored proc, just for grins. I have a feeling the problem lies somewhere in the way the cursor was being executed, and it was somehow giving rise to the Java process being suspended, but why a different client should give rise to this different locking/waiting behaviour when nothing else is running and the same execution plan is in operation is a little beyond my skills (I'm no DBA!). As a result, I have decided that 4 days is enough of anyone's time to waste on something like this, so I will grudgingly code around it (if I'm honest, the stored procedure needed re-coding to be more incremental instead of re-calculating all data each week anyway), and chalk this one down to experience. I'll leave the question open, big thanks to everyone who put their hat in the ring, it was all useful, and if anyone comes up with anything further, I'd love to hear some more options...and if anyone finds this post as a result of seeing this behaviour in their own environments, then hopefully there's some pointers here that you can try yourself, and hope fully see further than we did. I'm ready for my weekend now! -James

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• Designing interfaces: predict methods needed, discipline yourself and deal with code that comes to m

  - by fireeyedboy

  Was: Design by contract: predict methods needed, discipline yourself and deal with code that comes to mind I like the idea of designing by contract a lot (at least, as far as I understand the principal). I believe it means you define intefaces first before you start implementing actual code, right? However, from my limited experience (3 OOP years now) I usually can't resist the urge to start coding pretty early, for several reasons: because my limited experience has shown me I am unable to predict what methods I will be needing in the interface, so I might as well start coding right away. or because I am simply too impatient to write out the whole interfaces first. or when I do try it, I still wind up implementing bits of code already, because I fear I might forget this or that imporant bit of code, that springs to mind when I am designing the interfaces. As you see, especially with the last two points, this leads to a very disorderly way of doing things. Tasks get mixed up. I should draw a clear line between designing interfaces and actual coding. If you, unlike me, are a good/disciplined planner, as intended above, how do you: ...know the majority of methods you will be needing up front so well? Especially if it's components that implement stuff you are not familiar with yet. ...resist the urge to start coding right away? ...deal with code that comes to mind when you are designing the interfaces? UPDATE: Thank you for the answers so far. Valuable insights! And... I stand corrected; it seems I misinterpreted the idea of Design By Contract. For clarity, what I actually meant was: "coming up with interface methods before implementing the actual components". An additional thing that came up in my mind is related to point 1): b) How do you know the majority of components you will be needing. How do you flesh out these things before you start actually coding? For arguments sake, let's say I'm a novice with the MVC pattern, and I wanted to implement such a component/architecture. A naive approach would be to think of: a front controller some abstract action controller some abstract view ... and be done with it, so to speak. But, being more familiar with the MVC pattern, I know now that it makes sense to also have: a request object a router a dispatcher a response object view helpers etc.. etc.. If you map this idea to some completely new component you want to develop, with which you have no experience yet; how do you come up with these sort of additional components without actually coding the thing, and stuble upon the ideas that way? How would you know up front how fine grained some components should be? Is this a matter of disciplining yourself to think it out thoroughly? Or is it a matter of being good at thinking in abstractions?

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• Exposing model object using bindings in custom NSCell of NSTableView

  - by Hooligancat

  I am struggling trying to perform what I would think would be a relatively common task. I have an NSTableView that is bound to it's array via an NSArrayController. The array controller has it's content set to an NSMutableArray that contains one or more NSObject instances of a model class. What I don't know how to do is expose the model inside the NSCell subclass in a way that is bindings friendly. For the purpose of illustration, we'll say that the object model is a person consisting of a first name, last name, age and gender. Thus the model would appear something like this: @interface PersonModel : NSObject { NSString * firstName; NSString * lastName; NSString * gender; int * age; } Obviously the appropriate setters, getters init etc for the class. In my controller class I define an NSTableView, NSMutableArray and an NSArrayController: @interface ControllerClass : NSObject { IBOutlet NSTableView * myTableView; NSMutableArray * myPersonArray; IBOutlet NSArrayController * myPersonArrayController; } Using Interface Builder I can easily bind the model to the appropriate columns: myPersonArray --> myPersonArrayController --> table column binding This works fine. So I remove the extra columns, leaving one column hidden that is bound to the NSArrayController (this creates and keeps the association between each row and the NSArrayController) so that I am down to one visible column in my NSTableView and one hidden column. I create an NSCell subclass and put the appropriate drawing method to create the cell. In my awakeFromNib I establish the custom NSCell subclass: PersonModel * aCustomCell = [[[PersonModel alloc] init] autorelease]; [[myTableView tableColumnWithIdentifier:@"customCellColumn"] setDataCell:aCustomCell]; This, too, works fine from a drawing perspective. I get my custom cell showing up in the column and it repeats for every managed object in my array controller. If I add an object or remove an object from the array controller the table updates accordingly. However... I was under the impression that my PersonModel object would be available from within my NSCell subclass. But I don't know how to get to it. I don't want to set each NSCell using setters and getters because then I'm breaking the whole model concept by storing data in the NSCell instead of referencing it from the array controller. And yes I do need to have a custom NSCell, so having multiple columns is not an option. Where to from here? In addition to the Google and StackOverflow search, I've done the obligatory walk through on Apple's docs and don't seem to have found the answer. I have found a lot of references that beat around the bush but nothing involving an NSArrayController. The controller makes life very easy when binding to other elements of the model entity (such as a master/detail scenario). I have also found a lot of references (although no answers) when using Core Data, but Im not using Core Data. As per the norm, I'm very grateful for any assistance that can be offered!

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• MySQL Query GROUP_CONCAT Over Multiple Rows

  - by PeteGO

  I'm getting name and address data out of generic question / answer data to create some kind of normalised reporting database. The query I've got uses group_concat and works for individual sets of questions but not for multiple sets. I've tried to simplify what I'm doing by using just forename and surname and just 3 records, 2 for 1 person and 1 for another. In reality though there are more than 300,000 records. Example of results with qs.Id = 1. QuestionSetId Forename Surname ------------------------------------------------------- 1 Bob Jones Example of results with qs.Id IN (1, 2, 3). QuestionSetId Forename Surname ------------------------------------------------------- 3 Bob,Bob,Frank Jones,Jones,Smith What I would like to see for qs.Id IN (1, 2, 3). QuestionSetId Forename Surname ------------------------------------------------------- 1 Bob Jones 2 Bob Jones 3 Frank Smith So how can I make the 2nd example return a separate row for each set of name and address information? I realise the current way the data is stored is "questionable" but I cannot change the way the data is stored. I can get sets of individual answers but not sure how to combine the others. My simplified Schema that I cannot change: CREATE TABLE StaticQuestion ( Id INT NOT NULL, StaticText VARCHAR(500) NOT NULL); CREATE TABLE Question ( Id INT NOT NULL, Text VARCHAR(500) NOT NULL); CREATE TABLE StaticQuestionQuestionLink ( Id INT NOT NULL, StaticQuestionId INT NOT NULL, QuestionId INT NOT NULL, DateEffective DATETIME NOT NULL); CREATE TABLE Answer ( Id INT NOT NULL, Text VARCHAR(500) NOT NULL); CREATE TABLE QuestionSet ( Id INT NOT NULL, DateEffective DATETIME NOT NULL); CREATE TABLE QuestionAnswerLink ( Id INT NOT NULL, QuestionSetId INT NOT NULL, QuestionId INT NOT NULL, AnswerId INT NOT NULL, StaticQuestionId INT NOT NULL); Some example data for only forename and surname. INSERT INTO StaticQuestion (Id, StaticText) VALUES (1, 'FirstName'), (2, 'LastName'); INSERT INTO Question (Id, Text) VALUES (1, 'What is your first name?'), (2, 'What is your forename?'), (3, 'What is your Surname?'); INSERT INTO StaticQuestionQuestionLink (Id, StaticQuestionId, QuestionId, DateEffective) VALUES (1, 1, 1, '2001-01-01'), (2, 1, 2, '2008-08-08'), (3, 2, 3, '2001-01-01'); INSERT INTO Answer (Id, Text) VALUES (1, 'Bob'), (2, 'Jones'), (3, 'Bob'), (4, 'Jones'), (5, 'Frank'), (6, 'Smith'); INSERT INTO QuestionSet (Id, DateEffective) VALUES (1, '2002-03-25'), (2, '2009-05-05'), (3, '2009-08-06'); INSERT INTO QuestionAnswerLink (Id, QuestionSetId, QuestionId, AnswerId, StaticQuestionId) VALUES (1, 1, 1, 1, 1), (2, 1, 3, 2, 2), (3, 2, 2, 3, 1), (4, 2, 3, 4, 2), (5, 3, 2, 5, 1), (6, 3, 3, 6, 2); Just in case SQLFiddle is down here are the 3 queries from the examples I've linked to: 1: - working query but only on 1 set of data. SELECT MAX(QuestionSetId) AS QuestionSetId, GROUP_CONCAT(Forename) AS Forename, GROUP_CONCAT(Surname) AS Surname FROM (SELECT x.QuestionSetId, CASE x.StaticQuestionId WHEN 1 THEN Text END AS Forename, CASE x.StaticQuestionId WHEN 2 THEN Text END AS Surname FROM (SELECT (SELECT link.StaticQuestionId FROM StaticQuestionQuestionLink link WHERE link.Id = qa.QuestionId AND link.DateEffective <= qs.DateEffective AND link.StaticQuestionId IN (1, 2) ORDER BY link.DateEffective DESC LIMIT 1) AS StaticQuestionId, a.Text, qa.QuestionSetId FROM QuestionSet qs INNER JOIN QuestionAnswerLink qa ON qs.Id = qa.QuestionSetId INNER JOIN Answer a ON qa.AnswerId = a.Id WHERE qs.Id IN (1)) x) y 2: - working query but undesired results on multiple sets of data. SELECT MAX(QuestionSetId) AS QuestionSetId, GROUP_CONCAT(Forename) AS Forename, GROUP_CONCAT(Surname) AS Surname FROM (SELECT x.QuestionSetId, CASE x.StaticQuestionId WHEN 1 THEN Text END AS Forename, CASE x.StaticQuestionId WHEN 2 THEN Text END AS Surname FROM (SELECT (SELECT link.StaticQuestionId FROM StaticQuestionQuestionLink link WHERE link.Id = qa.QuestionId AND link.DateEffective <= qs.DateEffective AND link.StaticQuestionId IN (1, 2) ORDER BY link.DateEffective DESC LIMIT 1) AS StaticQuestionId, a.Text, qa.QuestionSetId FROM QuestionSet qs INNER JOIN QuestionAnswerLink qa ON qs.Id = qa.QuestionSetId INNER JOIN Answer a ON qa.AnswerId = a.Id WHERE qs.Id IN (1, 2, 3)) x) y 3: - working query on multiple sets of data only on 1 field (answer) though. SELECT qs.Id AS QuestionSet, a.Text AS Answer FROM QuestionSet qs INNER JOIN QuestionAnswerLink qalink ON qs.Id = qalink.QuestionSetId INNER JOIN StaticQuestionQuestionLink sqqlink ON qalink.QuestionId = sqqlink.QuestionId INNER JOIN Answer a ON qalink.AnswerId = a.Id WHERE sqqlink.StaticQuestionId = 1 /* FirstName */ AND sqqlink.DateEffective = (SELECT DateEffective FROM StaticQuestionQuestionLink WHERE StaticQuestionId = 1 AND DateEffective <= qs.DateEffective ORDER BY DateEffective DESC LIMIT 1)

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• How do I make Linux recognize a new SATA /dev/sda drive I hot swapped in without rebooting?

  - by Philip Durbin

  Hot swapping out a failed SATA /dev/sda drive worked fine, but when I went to swap in a new drive, it wasn't recognized: [root@fs-2 ~]# tail -18 /var/log/messages May 5 16:54:35 fs-2 kernel: ata1: exception Emask 0x10 SAct 0x0 SErr 0x50000 action 0xe frozen May 5 16:54:35 fs-2 kernel: ata1: SError: { PHYRdyChg CommWake } May 5 16:54:40 fs-2 kernel: ata1: link is slow to respond, please be patient (ready=0) May 5 16:54:45 fs-2 kernel: ata1: device not ready (errno=-16), forcing hardreset May 5 16:54:45 fs-2 kernel: ata1: soft resetting link May 5 16:54:50 fs-2 kernel: ata1: link is slow to respond, please be patient (ready=0) May 5 16:54:55 fs-2 kernel: ata1: SRST failed (errno=-16) May 5 16:54:55 fs-2 kernel: ata1: soft resetting link May 5 16:55:00 fs-2 kernel: ata1: link is slow to respond, please be patient (ready=0) May 5 16:55:05 fs-2 kernel: ata1: SRST failed (errno=-16) May 5 16:55:05 fs-2 kernel: ata1: soft resetting link May 5 16:55:10 fs-2 kernel: ata1: link is slow to respond, please be patient (ready=0) May 5 16:55:40 fs-2 kernel: ata1: SRST failed (errno=-16) May 5 16:55:40 fs-2 kernel: ata1: limiting SATA link speed to 1.5 Gbps May 5 16:55:40 fs-2 kernel: ata1: soft resetting link May 5 16:55:45 fs-2 kernel: ata1: SRST failed (errno=-16) May 5 16:55:45 fs-2 kernel: ata1: reset failed, giving up May 5 16:55:45 fs-2 kernel: ata1: EH complete I tried a couple things to make the server find the new /dev/sda, such as rescan-scsi-bus.sh but they didn't work: [root@fs-2 ~]# echo "---" > /sys/class/scsi_host/host0/scan -bash: echo: write error: Invalid argument [root@fs-2 ~]# [root@fs-2 ~]# /root/rescan-scsi-bus.sh -l [snip] 0 new device(s) found. 0 device(s) removed. [root@fs-2 ~]# [root@fs-2 ~]# ls /dev/sda ls: /dev/sda: No such file or directory I ended up rebooting the server. /dev/sda was recognized, I fixed the software RAID, and everything is fine now. But for next time, how can I make Linux recognize a new SATA drive I have hot swapped in without rebooting? The operating system in question is RHEL5.3: [root@fs-2 ~]# cat /etc/redhat-release Red Hat Enterprise Linux Server release 5.3 (Tikanga) The hard drive is a Seagate Barracuda ES.2 SATA 3.0-Gb/s 500-GB, model ST3500320NS. Here is the lscpi output: [root@fs-2 ~]# lspci 00:00.0 RAM memory: nVidia Corporation MCP55 Memory Controller (rev a2) 00:01.0 ISA bridge: nVidia Corporation MCP55 LPC Bridge (rev a3) 00:01.1 SMBus: nVidia Corporation MCP55 SMBus (rev a3) 00:02.0 USB Controller: nVidia Corporation MCP55 USB Controller (rev a1) 00:02.1 USB Controller: nVidia Corporation MCP55 USB Controller (rev a2) 00:04.0 IDE interface: nVidia Corporation MCP55 IDE (rev a1) 00:05.0 IDE interface: nVidia Corporation MCP55 SATA Controller (rev a3) 00:05.1 IDE interface: nVidia Corporation MCP55 SATA Controller (rev a3) 00:05.2 IDE interface: nVidia Corporation MCP55 SATA Controller (rev a3) 00:06.0 PCI bridge: nVidia Corporation MCP55 PCI bridge (rev a2) 00:08.0 Bridge: nVidia Corporation MCP55 Ethernet (rev a3) 00:09.0 Bridge: nVidia Corporation MCP55 Ethernet (rev a3) 00:0a.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0b.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0c.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0d.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0e.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0f.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:18.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration 00:18.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map 00:18.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller 00:18.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control 00:19.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration 00:19.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map 00:19.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller 00:19.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control 03:00.0 VGA compatible controller: Matrox Graphics, Inc. MGA G200e [Pilot] ServerEngines (SEP1) (rev 02) 04:00.0 PCI bridge: NEC Corporation uPD720400 PCI Express - PCI/PCI-X Bridge (rev 06) 04:00.1 PCI bridge: NEC Corporation uPD720400 PCI Express - PCI/PCI-X Bridge (rev 06) Update: In perhaps a dozen cases, we've been forced to reboot servers because hot swap hasn't "just worked." Thanks for the answers to look more into the SATA controller. I've included the lspci output for the problematic system above (hostname: fs-2). I could still use some help understanding what exactly isn't supported hardware-wise in terms of hot swap for that system. Please let me know what other output besides lspci might be useful. The good news is that hot swap "just worked" today on one of our servers (hostname: www-1), which is very rare for us. Here is the lspci output: [root@www-1 ~]# lspci 00:00.0 RAM memory: nVidia Corporation MCP55 Memory Controller (rev a2) 00:01.0 ISA bridge: nVidia Corporation MCP55 LPC Bridge (rev a3) 00:01.1 SMBus: nVidia Corporation MCP55 SMBus (rev a3) 00:02.0 USB Controller: nVidia Corporation MCP55 USB Controller (rev a1) 00:02.1 USB Controller: nVidia Corporation MCP55 USB Controller (rev a2) 00:04.0 IDE interface: nVidia Corporation MCP55 IDE (rev a1) 00:05.0 IDE interface: nVidia Corporation MCP55 SATA Controller (rev a3) 00:05.1 IDE interface: nVidia Corporation MCP55 SATA Controller (rev a3) 00:05.2 IDE interface: nVidia Corporation MCP55 SATA Controller (rev a3) 00:06.0 PCI bridge: nVidia Corporation MCP55 PCI bridge (rev a2) 00:08.0 Bridge: nVidia Corporation MCP55 Ethernet (rev a3) 00:09.0 Bridge: nVidia Corporation MCP55 Ethernet (rev a3) 00:0b.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0c.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0f.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:18.0 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] HyperTransport Configuration 00:18.1 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] Address Map 00:18.2 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] DRAM Controller 00:18.3 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] Miscellaneous Control 00:18.4 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] Link Control 00:19.0 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] HyperTransport Configuration 00:19.1 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] Address Map 00:19.2 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] DRAM Controller 00:19.3 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] Miscellaneous Control 00:19.4 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] Link Control 03:00.0 VGA compatible controller: Matrox Graphics, Inc. MGA G200e [Pilot] ServerEngines (SEP1) (rev 02) 04:00.0 PCI bridge: NEC Corporation uPD720400 PCI Express - PCI/PCI-X Bridge (rev 06) 04:00.1 PCI bridge: NEC Corporation uPD720400 PCI Express - PCI/PCI-X Bridge (rev 06) 09:00.0 SCSI storage controller: LSI Logic / Symbios Logic SAS1064ET PCI-Express Fusion-MPT SAS (rev 04)

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• Oracle data warehouse design - fact table acting as a dimension?

  - by Elizabeth

  THANKS: Both answers here are very helpful, but I could only pick one. I really appreciate the advice! our datawarehouse will be used more for workflow reports than traditional analytical reports. Our users care about "current picture" far more than history. (though history matters, too.) We are a government entity that does not have costs or related calculations. Mostly just counts of people within given locations and with related history. We are using Oracle, and I have found distinct advantage in using the star join whenever possible and would like to rearchitect everything to as closely resemble the star schema as is reasonable for our business uses. Speed in this DW is vital, and a number of tests have already proven the star schema approach to me. Our "person" table is key - it contains over 4 million records and will be the most frequently used source in queries. It can be seen at the center of a star with multiple dimensions (like age, gender, affiliation, location, etc.). It is a very LONG table, particularly when I join it to the address and contact information. However, it is more like a dimension table when we start looking at history. For example, there are two different history tables that have a person key pointing to the person table. One has over 20 million records and the other has almost 50 million and grows daily. Is this table a fact table or a dimension table? Can one work as both? If so, is that going to be a big performance problem? Is it common to query more off of a dimension than a fact? What happens if a DIFFERENT fact table that uses the person table as a dimension is actually only 60,000 records (much smaller.). I think my problem is that our data and use of it does not fit with the commonly use examples of star schemas. CLARIFICATION: Some good thoughts have been added below, but perhaps I left too much out to really explain well. Here's some more info: We handle a voter database. We don't have any measures except voter counts by various groups: voter counts by party, by age, by location; voter counts by ballot type and election, by ballot status and election, etc. We do have a "voting history" log as well as an activity audit log (change of address, party, etc.). We have information on which voters are election workers and all that related information. I figure I'll get to the peripheral stuff later. For now I'm focusing on our two major "business processes": voter registration(which IS a voter.) and election turnout. In the first, voter is a fact. In the second, voter is a dimension, along with party, election, and type of ballot. (and in case anyone is worried - no we don't know HOW people vote. Just that they do. LOL ) I hope that clarifies things a bit.

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• Macports irssi & perl5 installation issues

  - by Dmitri DB

  Long time reader, first time poster. Big, appreciative thanks for everyone's collective questioning and answering here and at stackoverflow, it's helped me quite a lot over the time I've been learning answers through these sites! Apologies in advance if I didn't search hard enough on posts already up on this site to find out what I could do about this issue, but I thought I'd just reach out for the sake of trying at least once. I've experienced this issue while starting up my macports-installed version of irssi: 13:25 -!- Irssi: Error in script dispatch: 13:25 Can't locate lib.pm in @INC (@INC contains: /opt/local/lib/perl5/site_perl/5.12.4/darwin-multi-2level /opt/local/lib/perl5/site_perl/5.12.4 /opt/local/lib/perl5/vendor_perl/5.12.4/darwin-multi-2level /opt/local/lib/perl5/vendor_perl/5.12.4 /opt/local/lib/perl5/5.12.4/darwin-multi-2level /opt/local/lib/perl5/5.12.4 /opt/local/lib/perl5/site_perl/5.12.3/darwin-multi-2level /opt/local/lib/perl5/site_perl/5.12.3 /opt/local/lib/perl5/site_perl /opt/local/lib/perl5/vendor_perl .) at (eval 18) line 1. 13:25 BEGIN failed--compilation aborted at (eval 18) line 1. 13:25 Huh, strange. I looked into it a bit: [email protected] /opt/local/lib/perl5 ?- find . -name "lib.pm" -ls 14673887 16 -r--r--r-- 1 root admin 6853 25 Jun 23:39 ./5.12.4/darwin-thread-multi- 2level/lib.pm [email protected] /opt/local/lib/perl5 ?- l 5.12.4/darwin-thread-multi-2level total 1864 drwxr-xr-x 55 root admin 1870 28 Jun 19:28 . drwxr-xr-x 158 root admin 5372 28 Jun 19:28 .. -rw-r--r-- 1 root admin 177814 25 Jun 23:39 .packlist drwxr-xr-x 6 root admin 204 28 Jun 19:28 B -r--r--r-- 1 root admin 25714 25 Jun 23:39 B.pm drwxr-xr-x 64 root admin 2176 28 Jun 19:28 CORE drwxr-xr-x 3 root admin 102 28 Jun 19:28 Compress -r--r--r-- 1 root admin 3000 25 Jun 23:39 Config.pm -r--r--r-- 1 root admin 228094 25 Jun 23:39 Config.pod -r--r--r-- 1 root admin 409 25 Jun 23:39 Config_git.pl -r--r--r-- 1 root admin 38759 25 Jun 23:39 Config_heavy.pl -r--r--r-- 1 root admin 21174 25 Jun 23:39 Cwd.pm -r--r--r-- 1 root admin 63535 25 Jun 23:39 DB_File.pm drwxr-xr-x 3 root admin 102 28 Jun 19:28 Data drwxr-xr-x 5 root admin 170 28 Jun 19:28 Devel drwxr-xr-x 4 root admin 136 28 Jun 19:28 Digest -r--r--r-- 1 root admin 25185 25 Jun 23:39 DynaLoader.pm drwxr-xr-x 22 root admin 748 28 Jun 19:28 Encode -r--r--r-- 1 root admin 29731 25 Jun 23:39 Encode.pm -r--r--r-- 1 root admin 6736 25 Jun 23:39 Errno.pm -r--r--r-- 1 root admin 5445 25 Jun 23:39 Fcntl.pm drwxr-xr-x 5 root admin 170 28 Jun 19:28 File drwxr-xr-x 3 root admin 102 28 Jun 19:28 Filter -r--r--r-- 1 root admin 1819 25 Jun 23:39 GDBM_File.pm drwxr-xr-x 4 root admin 136 28 Jun 19:28 Hash drwxr-xr-x 3 root admin 102 28 Jun 19:28 I18N drwxr-xr-x 11 root admin 374 28 Jun 19:28 IO -r--r--r-- 1 root admin 1404 25 Jun 23:39 IO.pm drwxr-xr-x 6 root admin 204 28 Jun 19:28 IPC drwxr-xr-x 4 root admin 136 28 Jun 19:28 List drwxr-xr-x 4 root admin 136 28 Jun 19:28 MIME drwxr-xr-x 3 root admin 102 28 Jun 19:28 Math -r--r--r-- 1 root admin 2519 25 Jun 23:39 NDBM_File.pm -r--r--r-- 1 root admin 4208 25 Jun 23:39 O.pm -r--r--r-- 1 root admin 15563 25 Jun 23:39 Opcode.pm -r--r--r-- 1 root admin 21011 25 Jun 23:39 POSIX.pm -r--r--r-- 1 root admin 58962 25 Jun 23:39 POSIX.pod drwxr-xr-x 5 root admin 170 28 Jun 19:28 PerlIO -r--r--r-- 1 root admin 2515 25 Jun 23:39 SDBM_File.pm drwxr-xr-x 4 root admin 136 28 Jun 19:28 Scalar -r--r--r-- 1 root admin 10837 25 Jun 23:39 Socket.pm -r--r--r-- 1 root admin 41003 25 Jun 23:39 Storable.pm drwxr-xr-x 4 root admin 136 28 Jun 19:28 Sys drwxr-xr-x 3 root admin 102 28 Jun 19:28 Text drwxr-xr-x 5 root admin 170 28 Jun 19:28 Time drwxr-xr-x 3 root admin 102 28 Jun 19:28 Unicode -r--r--r-- 1 root admin 14462 25 Jun 23:39 attributes.pm drwxr-xr-x 38 root admin 1292 28 Jun 19:28 auto -r--r--r-- 1 root admin 19892 25 Jun 23:39 encoding.pm -r--r--r-- 1 root admin 6853 25 Jun 23:39 lib.pm -r--r--r-- 1 root admin 11044 25 Jun 23:39 mro.pm -r--r--r-- 1 root admin 997 25 Jun 23:39 ops.pm -r--r--r-- 1 root admin 13945 25 Jun 23:39 re.pm drwxr-xr-x 3 root admin 102 28 Jun 19:28 threads -r--r--r-- 1 root admin 33283 25 Jun 23:39 threads.pm So, it sort of seems to me that the permissions which perl5 got installed with for these modules has gotten mixed up somehow? I'm not really a perl user beyond enjoying it for massive directory-recursive find/replace operations within text files, so I haven't much of an idea what the permissions here are supposed to look like, and I'm not really sure how to go about determining how macports has gone and installed perl this way when it's otherwise worked without failure for years now. Does anyone have any recommendations for the sanest path towards rectifying this issue? Also, is there any interesting reason as to why the macports default for the perl5 port installs 5.12.4, and not 5.16.0, which has to be explicitly installed via the perl5.16 port? Thanks again!

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• Rails & combo box change event: Help make this obtrusive javascript unobtrusive

  - by DJTripleThreat

  Ok so a friend of mine gave some help with a prototype/obtrusive solution to this but its not quite there. Also, I want to make this unobtrusive instead of using the observe_field function that rails gives me. I don't want to use prototype either because I'm more familiar with JQuery. Here's my problem: I have an Event that can have multiple ServiceTypes and a ServiceType can belong to many Events. A many-to-many relationship between these two exists as an OfferedService. When creating an event, I have a drop down with a list of TimeAllotments that are something like 10 minutes, 12 minutes, 15 minutes, 20 minutes, 30 minutes etc. When the user selects one of these choices, I want a div tag to be filled with a list of ServiceTypes that are associated with this TimeAllotment. So for example, the user selects "10 minutes" and then the div repopulates with services that last 10 minutes. Here is what I have so far: ... some erb code etc and then <fieldset> <legend><%= f.label :time_allotment, "Size of the Appointment Slots:" %></legend> <div> <span class="field-group"> <div> <!-- TimeAllotment is a tabless model which is why this is done like so... --> <%= select("event_service", "time_allotment", TimeAllotment.all.collect {|ta| [ta.title, ta.value]}, {:prompt => true}) %> </div> </span> </div> <div style="clear:both;"></div> Services: <div> <span class="field-group"> <!-- this div right here needs to be repopulated when the above select changes. --> <div id="services"> <% for service_type in ServiceType.all %> <div> <%= check_box_tag "event_service[service_type_ids][]", service_type.id, false %> <%=h service_type.title %> </div> <% end %> </div> </span> </div> <div class="clear"></div> </fieldset> ok so right now ALL of the services are there to be chosen from. I want them to change based on what is selected in the combobox event_service_time_allotment. Can someone help me get pointed in the right direction? I have looked at Ryan's rails casts for using JQuery but its not helpful because he deals with ajax calls for the create action. This would be for the new or edit action. I have a new.js.erb but it doesn't get loaded when calling the new action. I'm super lost as far as getting JQuery to work with my application. I think that if someone can just show me how to make an alert pop up when I change the combo box, and how to return a dataset using ajax the right now, I think I can figure out the rest. Thanks, I know this is super complicated so any helpful answers will get an upvote.

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• SVN: Release branch headaches, how to merge in website revisions as and when cleared to go live?

  - by Pete Duncanson

  I need a sanity check here if we can, any ideas on correcting/changing the following are very welcome! We've been getting ourselves in knots of late with our SVN and are trying to correct it by putting a Trunk/Release system in place. We have a large website that we develop on and we store it all in SVN. Heres what we had in mind: We have trunk and a release branch All work gets checked into Trunk. When a feature is deemed ready for the next release it is merged into a Release branch. We only have one release branch and just tag "Latest" when we do a push to live We hope to be able to get all the files changed from Latest to Head to give us a zip that we can upload (any ideas on an easy way to do this via scripting?) So we set all this up and where very happy with ourselves. Except its not working and heres why. We work on lots a different features/fixes/problems at once and they don't all get nicely checked in feature complete (but always working at least). Then sometimes you have to wait for Clients to sign off. As a result you end up with revisions which are "ready for live" being scattered with ones which are "still being worked on" in trunk. That means that the completed revisions are not getting merged in sequentially but out of order. I thought SVN could handle this, clever little thing it is, but apparently not. Heres an example: Pete changes some CSS to make a new button look pretty (Revision 1) Dave add some CSS to the bottom of the same CSS file as Pete's for a new feature (Revision 2) Dave's mod gets the nod so he merges it into Release and commits it with a log message mentioning revision number and bug tracking id. Pete adds more buttons to finish this mod, no CSS changes here though (Revision 3) Pete then merges his mods (Revision 1 and 3) into the Head of Release (which has Daves merge in it) but this over-writes Daves CSS additions which now dissapear completely. This leads to the site being broken and the Release branch being pretty much useless. So we tried some other ideas like reverting Release back to "Latest" and then just merging in all the Revisions 1,2 and 3 in order. This worked fine until we had Revision 4 which was not ready for live and Revision 5 which was. Suddenly we are getting ourselves in knots again with exactly the same problem! Ok so take three. Revert to Latest, merge in Revision 5, then do any update back to Head. Tree conflicts galore! So thats a no no. I cracked in the end and built it all up manaually but its not something I want to do regular, ideally I want to script our deployment but can't while Release is in such a mess. HELP! What the heck are we doing wrong? I can't seem to find any solutions to this problem of wanting different none sequential Revisions in Release. If its not possible thats fine but how the heck are we meant to get stuff live easily. We can't branch for every single change, the site takes 30 minutes+ to check out it would take too long. Side note, we are using TortoiseSVN so can we keep command line examples to a minimum in any answers? Latest version of TSVN and SVN Version 1.6 so we have the funky merge tracking etc. EDIT: An excellent blog post which deals with the dev/release cycle (although using GIT but still relivant) thought everyone would like to read it if they found this question interesting. (http://nvie.com/git-model) EDIT 2: I wrote a blog post on how to show which branch you are working on in your website which others have asked me about (http://www.offroadcode.com/2010/5/14/which-svn-branch-are-you-working-on.aspx). Hope that helps. In the meantime we are looking at Kiln and hoping to make the switch next month (gulp!)

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• Implementing a popularity algorithm in Django

  - by TheLizardKing

  I am creating a site similar to reddit and hacker news that has a database of links and votes. I am implementing hacker news' popularity algorithm and things are going pretty swimmingly until it comes to actually gathering up these links and displaying them. The algorithm is simple: Y Combinator's Hacker News: Popularity = (p - 1) / (t + 2)^1.5` Votes divided by age factor. Where` p : votes (points) from users. t : time since submission in hours. p is subtracted by 1 to negate submitter's vote. Age factor is (time since submission in hours plus two) to the power of 1.5.factor is (time since submission in hours plus two) to the power of 1.5. I asked a very similar question over yonder http://stackoverflow.com/questions/1964395/complex-ordering-in-django but instead of contemplating my options I choose one and tried to make it work because that's how I did it with PHP/MySQL but I now know Django does things a lot differently. My models look something (exactly) like this class Link(models.Model): category = models.ForeignKey(Category) user = models.ForeignKey(User) created = models.DateTimeField(auto_now_add = True) modified = models.DateTimeField(auto_now = True) fame = models.PositiveIntegerField(default = 1) title = models.CharField(max_length = 256) url = models.URLField(max_length = 2048) def __unicode__(self): return self.title class Vote(models.Model): link = models.ForeignKey(Link) user = models.ForeignKey(User) created = models.DateTimeField(auto_now_add = True) modified = models.DateTimeField(auto_now = True) karma_delta = models.SmallIntegerField() def __unicode__(self): return str(self.karma_delta) and my view: def index(request): popular_links = Link.objects.select_related().annotate(karma_total = Sum('vote__karma_delta')) return render_to_response('links/index.html', {'links': popular_links}) Now from my previous question, I am trying to implement the algorithm using the sorting function. An answer from that question seems to think I should put the algorithm in the select and sort then. I am going to paginate these results so I don't think I can do the sorting in python without grabbing everything. Any suggestions on how I could efficiently do this? EDIT This isn't working yet but I think it's a step in the right direction: from django.shortcuts import render_to_response from linkett.apps.links.models import * def index(request): popular_links = Link.objects.select_related() popular_links = popular_links.extra( select = { 'karma_total': 'SUM(vote.karma_delta)', 'popularity': '(karma_total - 1) / POW(2, 1.5)', }, order_by = ['-popularity'] ) return render_to_response('links/index.html', {'links': popular_links}) This errors out into: Caught an exception while rendering: column "karma_total" does not exist LINE 1: SELECT ((karma_total - 1) / POW(2, 1.5)) AS "popularity", (S... EDIT 2 Better error? TemplateSyntaxError: Caught an exception while rendering: missing FROM-clause entry for table "vote" LINE 1: SELECT ((vote.karma_total - 1) / POW(2, 1.5)) AS "popularity... My index.html is simply: {% block content %} {% for link in links %} karma-up {{ link.karma_total }} karma-down {{ link.title }} Posted by {{ link.user }} to {{ link.category }} at {{ link.created }} {% empty %} No Links {% endfor %} {% endblock content %} EDIT 3 So very close! Again, all these answers are great but I am concentrating on a particular one because I feel it works best for my situation. from django.db.models import Sum from django.shortcuts import render_to_response from linkett.apps.links.models import * def index(request): popular_links = Link.objects.select_related().extra( select = { 'popularity': '(SUM(links_vote.karma_delta) - 1) / POW(2, 1.5)', }, tables = ['links_link', 'links_vote'], order_by = ['-popularity'], ) return render_to_response('links/test.html', {'links': popular_links}) Running this I am presented with an error hating on my lack of group by values. Specifically: TemplateSyntaxError at / Caught an exception while rendering: column "links_link.id" must appear in the GROUP BY clause or be used in an aggregate function LINE 1: ...karma_delta) - 1) / POW(2, 1.5)) AS "popularity", "links_lin... Not sure why my links_link.id wouldn't be in my group by but I am not sure how to alter my group by, django usually does that.

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• Problem installing Ubuntu 10.04 64 bit side by side with Vista by using a bootable USB drive. What n

  - by Adam Siddhi

  What happened I decided to install Ubuntu 10.04 64 bit side by side with Vista Home Premium (I guess on another partition) with a USB stick. I found instructions on how to do this here: https://help.ubuntu.com/community/Installation/FromUSBStick To create the bootable USB drive I had to download a program called Unetbootin. That process was simple enough. All I had to do was just choose the disk image option, select the ubuntu-10.04-desktop-amd64.iso image, make sure it recognizes my USB drive and then press OK. It takes only like a few minutes to create a working bootable USB drive. Then I have to restart my computer, enter the BIOS, select my USB drive as the first boot drive, save options and continue with booting up. After this Ubuntu actually loads up. I think this is known as the Live version of Ubuntu so you can try it out before fully installing it. Any ways, on the Ubuntu 10.04 desktop I saw an installer. I click it and begin the installation process. Just so you know, I tried installing it 2 times. I will explain what happened each time: The first time I tried installing Ubuntu 10.04 I got stuck at step 4 of 7. I remember selecting the last option in the window which was Specify Partitions Manually (Advanced) I made my partition for Ubuntu like 52 gigs. I clicked forward and a little pop up window appeared saying Please Wait. So the installation process stalled on this window so I closed out of it and quit the installation process. So at this point I was worried because I had already selected the partition size and assumed it started making it. Since it stalled I had to quit out though. Anyways, once again I reached step 4 of 7 a decided to select the first option which is Install them side by side choosing between them each startup. I figured this was the safe way to go. I did that and the pop up window saying Please Wait popped up again but lasted only like 10 seconds. Then I got to I guess step 6 where it asks you to enter your desired name and password. Did that and clicked forward. The Ubuntu 10.04 installation load screen appeared and the loading bar at the bottom started filling up. So I got to 83% and stalled during the Importing other profile information (I think it was called this. I had the option to do this during I think step 6) process. So at this point I decided to get stop the installation process. I was getting very nervous. I tried to restart the computer but all that happened was that Ubuntu restarted. I finally got the computer to restart. I was pretty sure I had screwed something up big time by this point. As my computer was restarting I entered BIOS again and switched back to it booting from my main hard drive containing Vista. Saved it and continued the boot process. My worst fears were confirmed as Vista would not boot up. I mean I saw the little Microsoft Windows choppy animated green loading bar at the bottom of the screen and then boom! It decided to restart. When it restarted I had the option to run a memory test check to see if there was anything that needed to be repaired. That took like 20 minutes and at the end I saw that I did indeed have to repair something. I had to go through 2 repair processes. After each I had to restart the computer. The 2nd time it went through the repair process it said that it could not fully repair the damage. I was scared and restarted but Vista did load up. I got to my desktop and saw a message saying something like Repairs have been made, Please restart for changes to take effect I noticed that some Notification icons were missing and I could not hear volume in a video. Things were a bit funky. So I did restart and here I am. Now what?! So since I got back into Vista and thankfully have a working Internet connection I am trying to find answers to my problem (that is why I am writing this post). I am scared that I have partioned my hard drive 2 times after researching Installing Ubuntu 10.04 and seeing this post http://techie-buzz.com/foss/ubuntu-10-04-lts-installation-guide.html The author shows screen shots of installing Ubuntu 10.04. He shows the image of step 4 of 7 with a caption at the bottom. I will recreate it below: Select a partitioning option. Unless you want to format all the hard drive and install Ubuntu afresh, select the last option and proceed. Questions If I have indeed partitioned my HD 2 times (which I am sure it is), how do I get to a point where I can see all my bad, unfinished Ubuntu partitions and get rid of them? How do I clean this big mess up? & How can I ensure that this mess will not happen next time I try installing Ubuntu 10.04? Thank you Adam

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• Is SHA-1 secure for password storage?

  - by Tgr

  Some people throw around remarks like "SHA-1 is broken" a lot, so I'm trying to understand what exactly that means. Let's assume I have a database of SHA-1 password hashes, and an attacker whith a state of the art SHA-1 breaking algorithm and a botnet with 100,000 machines gets access to it. (Having control over 100k home computers would mean they can do about 10^15 operations per second.) How much time would they need to find out the password of any one user? find out the password of a given user? find out the password of all users? find a way to log in as one of the users? find a way to log in as a specific user? How does that change if the passwords are salted? Does the method of salting (prefix, postfix, both, or something more complicated like xor-ing) matter? Here is my current understanding, after some googling. Please correct in the answers if I misunderstood something. If there is no salt, a rainbow attack will immediately find all passwords (except extremely long ones). If there is a sufficiently long random salt, the most effective way to find out the passwords is a brute force or dictionary attack. Neither collision nor preimage attacks are any help in finding out the actual password, so cryptographic attacks against SHA-1 are no help here. It doesn't even matter much what algorithm is used - one could even use MD5 or MD4 and the passwords would be just as safe (there is a slight difference because computing a SHA-1 hash is slower). To evaluate how safe "just as safe" is, let's assume that a single sha1 run takes 1000 operations and passwords contain uppercase, lowercase and digits (that is, 60 characters). That means the attacker can test 1015*60*60*24 / 1000 ~= 1017 potential password a day. For a brute force attack, that would mean testing all passwords up to 9 characters in 3 hours, up to 10 characters in a week, up to 11 characters in a year. (It takes 60 times as much for every additional character.) A dictionary attack is much, much faster (even an attacker with a single computer could pull it off in hours), but only finds weak passwords. To log in as a user, the attacker does not need to find out the exact password; it is enough to find a string that results in the same hash. This is called a first preimage attack. As far as I could find, there are no preimage attacks against SHA-1. (A bruteforce attack would take 2160 operations, which means our theoretical attacker would need 1030 years to pull it off. Limits of theoretical possibility are around 260 operations, at which the attack would take a few years.) There are preimage attacks against reduced versions of SHA-1 with negligible effect (for the reduced SHA-1 which uses 44 steps instead of 80, attack time is down from 2160 operations to 2157). There are collision attacks against SHA-1 which are well within theoretical possibility (the best I found brings the time down from 280 to 252), but those are useless against password hashes, even without salting. In short, storing passwords with SHA-1 seems perfectly safe. Did I miss something?

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• BasicAuthProvider in ServiceStack

  - by Per

  I've got an issue with the BasicAuthProvider in ServiceStack. POST-ing to the CredentialsAuthProvider (/auth/credentials) is working fine. The problem is that when GET-ing (in Chrome): http://foo:pwd@localhost:81/tag/string/list the following is the result Handler for Request not found: Request.HttpMethod: GET Request.HttpMethod: GET Request.PathInfo: /login Request.QueryString: System.Collections.Specialized.NameValueCollection Request.RawUrl: /login?redirect=http%3a%2f%2flocalhost%3a81%2ftag%2fstring%2flist which tells me that it redirected me to /login instead of serving the /tag/... request. Here's the entire code for my AppHost: public class AppHost : AppHostHttpListenerBase, IMessageSubscriber { private ITagProvider myTagProvider; private IMessageSender mySender; private const string UserName = "foo"; private const string Password = "pwd"; public AppHost( TagConfig config, IMessageSender sender ) : base( "BM App Host", typeof( AppHost ).Assembly ) { myTagProvider = new TagProvider( config ); mySender = sender; } public class CustomUserSession : AuthUserSession { public override void OnAuthenticated( IServiceBase authService, IAuthSession session, IOAuthTokens tokens, System.Collections.Generic.Dictionary<string, string> authInfo ) { authService.RequestContext.Get<IHttpRequest>().SaveSession( session ); } } public override void Configure( Funq.Container container ) { Plugins.Add( new MetadataFeature() ); container.Register<BeyondMeasure.WebAPI.Services.Tags.ITagProvider>( myTagProvider ); container.Register<IMessageSender>( mySender ); Plugins.Add( new AuthFeature( () => new CustomUserSession(), new AuthProvider[] { new CredentialsAuthProvider(), //HTML Form post of UserName/Password credentials new BasicAuthProvider(), //Sign-in with Basic Auth } ) ); container.Register<ICacheClient>( new MemoryCacheClient() ); var userRep = new InMemoryAuthRepository(); container.Register<IUserAuthRepository>( userRep ); string hash; string salt; new SaltedHash().GetHashAndSaltString( Password, out hash, out salt ); // Create test user userRep.CreateUserAuth( new UserAuth { Id = 1, DisplayName = "DisplayName", Email = "[email protected]", UserName = UserName, FirstName = "FirstName", LastName = "LastName", PasswordHash = hash, Salt = salt, }, Password ); } } Could someone please tell me what I'm doing wrong with either the SS configuration or how I am calling the service, i.e. why does it not accept the supplied user/pwd? Update1: Request/Response captured in Fiddler2when only BasicAuthProvider is used. No Auth header sent in the request, but also no Auth header in the response. GET /tag/string/AAA HTTP/1.1 Host: localhost:81 Connection: keep-alive User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8,sv;q=0.6 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 Cookie: ss-pid=Hu2zuD/T8USgvC8FinMC9Q==; X-UAId=1; ss-id=1HTqSQI9IUqRAGxM8vKlPA== HTTP/1.1 302 Found Location: /login?redirect=http%3a%2f%2flocalhost%3a81%2ftag%2fstring%2fAAA Server: Microsoft-HTTPAPI/2.0 X-Powered-By: ServiceStack/3,926 Win32NT/.NET Date: Sat, 10 Nov 2012 22:41:51 GMT Content-Length: 0 Update2 Request/Response with HtmlRedirect = null . SS now answers with the Auth header, which Chrome then issues a second request for and authentication succeeds GET http://localhost:81/tag/string/Abc HTTP/1.1 Host: localhost:81 Connection: keep-alive User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8,sv;q=0.6 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 Cookie: ss-pid=Hu2zuD/T8USgvC8FinMC9Q==; X-UAId=1; ss-id=1HTqSQI9IUqRAGxM8vKlPA== HTTP/1.1 401 Unauthorized Transfer-Encoding: chunked Server: Microsoft-HTTPAPI/2.0 X-Powered-By: ServiceStack/3,926 Win32NT/.NET WWW-Authenticate: basic realm="/auth/basic" Date: Sat, 10 Nov 2012 22:49:19 GMT 0 GET http://localhost:81/tag/string/Abc HTTP/1.1 Host: localhost:81 Connection: keep-alive Authorization: Basic Zm9vOnB3ZA== User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8,sv;q=0.6 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 Cookie: ss-pid=Hu2zuD/T8USgvC8FinMC9Q==; X-UAId=1; ss-id=1HTqSQI9IUqRAGxM8vKlPA==

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• What are the Open Source alternatives to WPF/XAML?

  - by Evan Plaice

  If we've learned anything from HTML/CSS it's that, declarative languages (like XML) work best to describe User Interfaces because: It's easy to build code preprocessors that can template the code effectively. The code is in a well defined well structured (ideally) format so it's easy to parse. The technology to effectively parse or crawl an XML based source file already exists. The UIs scripted code becomes much simpler and easier to understand. It simple enough that designers are able to design the interface themselves. Programmers suck at creating UIs so it should be made easy enough for designers. I recently took a look at the meat of a WPF application (ie. the XAML) and it looks surprisingly familiar to the declarative language style used in HTML. It's apparent to me that the current state of desktop UI development is largely fractionalized, otherwise there wouldn't be so much duplicated effort in the domain of graphical user interface design (IE. GTK, XUL, Qt, Winforms, WPF, etc). There are 45 GUI platforms for Python alone It's seems reasonable to me that there should be a general purpose, open source, standardized, platform independent, markup language for designing desktop GUIs. Much like what the W3C made HTML/CSS into. WPF, or more specifically XAML seems like a pretty likely step in the right direction. Now that the 'browser wars' are over should we look forward to a future of 'desktop gui wars?' Note: This topic is relatively subjective in the attempt to be 'future-thinking.' I think that desktop GUI development in its current state sucks ((really)hard) and, even though WPF is still in it's infancy, it presents a likely solution to the problem. Update: Thanks a lot for the info, keep it comin'. Here's are the options I've gathered from the comments and answers. GladeXML Editor: Glade Interface Designer OS Platforms: All GUI Platform: GTK+ Languages: C (libglade), C++, C# (Glade#), Python, Ada, Pike, Perl, PHP, Eiffel, Ruby XRC (XML Resource) Editors: wxGlade, XRCed, wxDesigner, DialogBlocks (non-free) OS Platforms: All GUI Platform: wxWidgets Languages: C++, Python (wxPython), Perl (wxPerl), .NET (wx.NET) XML based formats that are either not free, not cross-platform, or language specific XUL Editor: Any basic text editor OS Platforms: Any OS running a browser that supports XUL GUI Platform: Gecko Engine? Languages: C++, Python, Ruby as plugin languages not base languages Note: I'm not sure if XUL deserves mentioning in this list because it's less of a desktop GUI language and more of a make-webapps-run-on-the-desktop language. Plus, it requires a browser to run. IE, it's 'DHTML for the desktop.' CookSwing Editor: Eclipse via WindowBuilder, NetBeans 5.0 (non-free) via Swing GUI Builder aka Matisse OS Platforms: All GUI Platform: Java Languages: Java only XAML (Moonlight) Editor: MonoDevelop OS Platforms: Linux and other Unix/X11 based OSes only GUI Platforms: GTK+ Languages: .NET Note: XAML is not a pure Open Source format because Microsoft controls its terms of use including the right to change the terms at any time. Moonlight can not legally be made to run on Windows or Mac. In addition, the only platform that is exempt from legal action is Novell. See this for a full description of what I mean.

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• How do I make Linux recognize a new SATA /dev/sda drive I hot swapped in without rebooting?

  - by Philip Durbin

  Hot swapping out a failed SATA /dev/sda drive worked fine, but when I went to swap in a new drive, it wasn't recognized: [root@fs-2 ~]# tail -18 /var/log/messages May 5 16:54:35 fs-2 kernel: ata1: exception Emask 0x10 SAct 0x0 SErr 0x50000 action 0xe frozen May 5 16:54:35 fs-2 kernel: ata1: SError: { PHYRdyChg CommWake } May 5 16:54:40 fs-2 kernel: ata1: link is slow to respond, please be patient (ready=0) May 5 16:54:45 fs-2 kernel: ata1: device not ready (errno=-16), forcing hardreset May 5 16:54:45 fs-2 kernel: ata1: soft resetting link May 5 16:54:50 fs-2 kernel: ata1: link is slow to respond, please be patient (ready=0) May 5 16:54:55 fs-2 kernel: ata1: SRST failed (errno=-16) May 5 16:54:55 fs-2 kernel: ata1: soft resetting link May 5 16:55:00 fs-2 kernel: ata1: link is slow to respond, please be patient (ready=0) May 5 16:55:05 fs-2 kernel: ata1: SRST failed (errno=-16) May 5 16:55:05 fs-2 kernel: ata1: soft resetting link May 5 16:55:10 fs-2 kernel: ata1: link is slow to respond, please be patient (ready=0) May 5 16:55:40 fs-2 kernel: ata1: SRST failed (errno=-16) May 5 16:55:40 fs-2 kernel: ata1: limiting SATA link speed to 1.5 Gbps May 5 16:55:40 fs-2 kernel: ata1: soft resetting link May 5 16:55:45 fs-2 kernel: ata1: SRST failed (errno=-16) May 5 16:55:45 fs-2 kernel: ata1: reset failed, giving up May 5 16:55:45 fs-2 kernel: ata1: EH complete I tried a couple things to make the server find the new /dev/sda, such as rescan-scsi-bus.sh but they didn't work: [root@fs-2 ~]# echo "---" > /sys/class/scsi_host/host0/scan -bash: echo: write error: Invalid argument [root@fs-2 ~]# [root@fs-2 ~]# /root/rescan-scsi-bus.sh -l [snip] 0 new device(s) found. 0 device(s) removed. [root@fs-2 ~]# [root@fs-2 ~]# ls /dev/sda ls: /dev/sda: No such file or directory I ended up rebooting the server. /dev/sda was recognized, I fixed the software RAID, and everything is fine now. But for next time, how can I make Linux recognize a new SATA drive I have hot swapped in without rebooting? The operating system in question is RHEL5.3: [root@fs-2 ~]# cat /etc/redhat-release Red Hat Enterprise Linux Server release 5.3 (Tikanga) The hard drive is a Seagate Barracuda ES.2 SATA 3.0-Gb/s 500-GB, model ST3500320NS. Here is the lscpi output: [root@fs-2 ~]# lspci 00:00.0 RAM memory: nVidia Corporation MCP55 Memory Controller (rev a2) 00:01.0 ISA bridge: nVidia Corporation MCP55 LPC Bridge (rev a3) 00:01.1 SMBus: nVidia Corporation MCP55 SMBus (rev a3) 00:02.0 USB Controller: nVidia Corporation MCP55 USB Controller (rev a1) 00:02.1 USB Controller: nVidia Corporation MCP55 USB Controller (rev a2) 00:04.0 IDE interface: nVidia Corporation MCP55 IDE (rev a1) 00:05.0 IDE interface: nVidia Corporation MCP55 SATA Controller (rev a3) 00:05.1 IDE interface: nVidia Corporation MCP55 SATA Controller (rev a3) 00:05.2 IDE interface: nVidia Corporation MCP55 SATA Controller (rev a3) 00:06.0 PCI bridge: nVidia Corporation MCP55 PCI bridge (rev a2) 00:08.0 Bridge: nVidia Corporation MCP55 Ethernet (rev a3) 00:09.0 Bridge: nVidia Corporation MCP55 Ethernet (rev a3) 00:0a.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0b.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0c.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0d.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0e.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0f.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:18.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration 00:18.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map 00:18.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller 00:18.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control 00:19.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration 00:19.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map 00:19.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller 00:19.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control 03:00.0 VGA compatible controller: Matrox Graphics, Inc. MGA G200e [Pilot] ServerEngines (SEP1) (rev 02) 04:00.0 PCI bridge: NEC Corporation uPD720400 PCI Express - PCI/PCI-X Bridge (rev 06) 04:00.1 PCI bridge: NEC Corporation uPD720400 PCI Express - PCI/PCI-X Bridge (rev 06) Update: In perhaps a dozen cases, we've been forced to reboot servers because hot swap hasn't "just worked." Thanks for the answers to look more into the SATA controller. I've included the lspci output for the problematic system above (hostname: fs-2). I could still use some help understanding what exactly isn't supported hardware-wise in terms of hot swap for that system. Please let me know what other output besides lspci might be useful. The good news is that hot swap "just worked" today on one of our servers (hostname: www-1), which is very rare for us. Here is the lspci output: [root@www-1 ~]# lspci 00:00.0 RAM memory: nVidia Corporation MCP55 Memory Controller (rev a2) 00:01.0 ISA bridge: nVidia Corporation MCP55 LPC Bridge (rev a3) 00:01.1 SMBus: nVidia Corporation MCP55 SMBus (rev a3) 00:02.0 USB Controller: nVidia Corporation MCP55 USB Controller (rev a1) 00:02.1 USB Controller: nVidia Corporation MCP55 USB Controller (rev a2) 00:04.0 IDE interface: nVidia Corporation MCP55 IDE (rev a1) 00:05.0 IDE interface: nVidia Corporation MCP55 SATA Controller (rev a3) 00:05.1 IDE interface: nVidia Corporation MCP55 SATA Controller (rev a3) 00:05.2 IDE interface: nVidia Corporation MCP55 SATA Controller (rev a3) 00:06.0 PCI bridge: nVidia Corporation MCP55 PCI bridge (rev a2) 00:08.0 Bridge: nVidia Corporation MCP55 Ethernet (rev a3) 00:09.0 Bridge: nVidia Corporation MCP55 Ethernet (rev a3) 00:0b.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0c.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:0f.0 PCI bridge: nVidia Corporation MCP55 PCI Express bridge (rev a3) 00:18.0 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] HyperTransport Configuration 00:18.1 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] Address Map 00:18.2 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] DRAM Controller 00:18.3 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] Miscellaneous Control 00:18.4 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] Link Control 00:19.0 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] HyperTransport Configuration 00:19.1 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] Address Map 00:19.2 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] DRAM Controller 00:19.3 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] Miscellaneous Control 00:19.4 Host bridge: Advanced Micro Devices [AMD] K10 [Opteron, Athlon64, Sempron] Link Control 03:00.0 VGA compatible controller: Matrox Graphics, Inc. MGA G200e [Pilot] ServerEngines (SEP1) (rev 02) 04:00.0 PCI bridge: NEC Corporation uPD720400 PCI Express - PCI/PCI-X Bridge (rev 06) 04:00.1 PCI bridge: NEC Corporation uPD720400 PCI Express - PCI/PCI-X Bridge (rev 06) 09:00.0 SCSI storage controller: LSI Logic / Symbios Logic SAS1064ET PCI-Express Fusion-MPT SAS (rev 04)

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• ListView with button and check mark?

  - by jgelderloos

  So I have looked through a lot of other answers but have not been able to get my app to work how I want it. I basically want the list view that has the text and check mark to the right, but then an addition button to the left. Right now my list view shows up but the check image is never changed. Selector: <?xml version="1.0" encoding="utf-8"?> <selector xmlns:android="http://schemas.android.com/apk/res/android"> <item android:state_selected="true" android:drawable="@drawable/accept_on" /> <item android:drawable="@drawable/accept" /> </selector> Row xml: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/layout" android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="fill_parent" android:padding="10dp" android:background="#EEE"> <ImageButton android:id="@+id/goToMapButton" android:src="@drawable/go_to_map" android:layout_width="wrap_content" android:layout_height="wrap_content" android:gravity="left" /> <TextView android:id="@+id/itemName" android:layout_width="fill_parent" android:layout_height="fill_parent" android:gravity="center_vertical" android:textColor="#000000" android:layout_marginTop="5dp" android:layout_marginBottom="5dp" android:layout_weight="1" /> <Button android:id="@+id/checkButton" android:background="@drawable/item_selector" android:layout_width="wrap_content" android:layout_height="wrap_content" android:gravity="right" /> </LinearLayout> MapAdapter: import android.content.Context; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ArrayAdapter; import android.widget.Button; import android.widget.ImageButton; import android.widget.LinearLayout; import android.widget.TextView; public class MapAdapter extends ArrayAdapter<String>{ Context context; int layoutResourceId; String data[] = null; LayoutInflater inflater; LinearLayout layout; public MapAdapter(Context context, int layoutResourceId, String[] data) { super(context, layoutResourceId, data); this.layoutResourceId = layoutResourceId; this.context = context; this.data = data; inflater = LayoutInflater.from(context); } @Override public String getItem(int position) { return data[position]; } @Override public View getView(int position, View convertView, ViewGroup parent) { ViewHolder holder = new ViewHolder(); if(convertView == null) { convertView = inflater.inflate(R.layout.map_item_row, null); layout = (LinearLayout)convertView.findViewById(R.id.layout); holder.map = (ImageButton)convertView.findViewById(R.id.goToMapButton); holder.name = (TextView)convertView.findViewById(R.id.itemName); //holder.check = (Button)convertView.findViewById(R.id.checkButton); convertView.setTag(holder); } else { holder = (ViewHolder) convertView.getTag(); } layout.setBackgroundColor(0x00000004); holder.name.setText(getItem(position)); return convertView; } static class ViewHolder { ImageButton map; TextView name; Button check; } }

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• A format for storing personal contacts in a database

  - by Gart

  I'm thinking of the best way to store personal contacts in a database for a business application. The traditional and straightforward approach would be to create a table with columns for each element, i.e. Name, Telephone Number, Job title, Address, etc... However, there are known industry standards for this kind of data, like for example vCard, or hCard, or vCard-RDF/XML or even Windows Contacts XML Schema. Utilizing an standard format would offer some benefits, like inter-operablilty with other systems. But how can I decide which method to use? The requirements are mainly to store the data. Search and ordering queries are highly unlikely but possible. The volume of the data is 100,000 records at maximum. My database engine supports native XML columns. I have been thinking to use some XML-based format to store the personal contacts. Then it will be possible to utilize XML indexes on this data, if searching and ordering is needed. Is this a good approach? Which contacts format and schema would you recommend for this? Edited after first answers Here is why I think the straightforward approach is bad. This is due to the nature of this kind of data - it is not that simple. The personal contacts it is not well-structured data, it may be called semi-structured. Each contact may have different data fields, maybe even such fields which I cannot anticipate. In my opinion, each piece of this data should be treated as important information, i.e. no piece of data could be discarded just because there was no relevant column in the database. If we took it further, assuming that no data may be lost, then we could create a big text column named Comment or Description or Other and put there everything which cannot be fitted well into table columns. But then again - the data would lose structure - this might be bad. If we wanted structured data then - according to the database design principles - the data should be decomposed into entities, and relations should be established between the entities. But this adds complexity - there are just too many entities, and lots of design desicions should be made, like "How do we store Address? Personal Name? Phone number? How do we encode home phone numbers and mobile phone numbers? How about other contact info?.." The relations between entities are complex and multiple, and each relation is a table in the database. Each relation needs to be documented in the design papers. That is a lot of work to do. But it is possible to avoid the complexity entirely - just document that the data is stored according to such and such standard schema, period. Then anybody who would be reading that document should easily understand what it was all about. Finally, this is all about using an industry standard. The standard is, hopefully, designed by some clever people who anticipated and described the structure of personal contacts information much better than I ever could. Why should we all reinvent the wheel?? It's much easier to use a standard schema. The problem is, there are just too many standards - it's not easy to decide which one to use!

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• Minimum-Waste Print Job Grouping Algorithm?

  - by Matt Mc

  I work at a publishing house and I am setting up one of our presses for "ganging", in other words, printing multiple jobs simultaneously. Given that different print jobs can have different quantities, and anywhere from 1 to 20 jobs might need to be considered at a time, the problem would be to determine which jobs to group together to minimize waste (waste coming from over-printing on smaller-quantity jobs in a given set, that is). Given the following stable data: All jobs are equal in terms of spatial size--placement on paper doesn't come into consideration. There are three "lanes", meaning that three jobs can be printed simultaneously. Ideally, each lane has one job. Part of the problem is minimizing how many lanes each job is run on. If necessary, one job could be run on two lanes, with a second job on the third lane. The "grouping" waste from a given set of jobs (let's say the quantities of them are x, y and z) would be the highest number minus the two lower numbers. So if x is the higher number, the grouping waste would be (x - y) + (x - z). Otherwise stated, waste is produced by printing job Y and Z (in excess of their quantities) up to the quantity of X. The grouping waste would be a qualifier for the given set, meaning it could not exceed a certain quantity or the job would simply be printed alone. So the question is stated: how to determine which sets of jobs are grouped together, out of any given number of jobs, based on the qualifiers of 1) Three similar quantities OR 2) Two quantities where one is approximately double the other, AND with the aim of minimal total grouping waste across the various sets. (Edit) Quantity Information: Typical job quantities can be from 150 to 350 on foreign languages, or 500 to 1000 on English print runs. This data can be used to set up some scenarios for an algorithm. For example, let's say you had 5 jobs: 1000, 500, 500, 450, 250 By looking at it, I can see a couple of answers. Obviously (1000/500/500) is not efficient as you'll have a grouping waste of 1000. (500/500/450) is better as you'll have a waste of 50, but then you run (1000) and (250) alone. But you could also run (1000/500) with 1000 on two lanes, (500/250) with 500 on two lanes and then (450) alone. In terms of trade-offs for lane minimization vs. wastage, we could say that any grouping waste over 200 is excessive. (End Edit) ...Needless to say, quite a problem. (For me.) I am a moderately skilled programmer but I do not have much familiarity with algorithms and I am not fully studied in the mathematics of the area. I'm I/P writing a sort of brute-force program that simply tries all options, neglecting any option tree that seems to have excessive grouping waste. However, I can't help but hope there's an easier and more efficient method. I've looked at various websites trying to find out more about algorithms in general and have been slogging my way through the symbology, but it's slow going. Unfortunately, Wikipedia's articles on the subject are very cross-dependent and it's difficult to find an "in". The only thing I've been able to really find would seem to be a definition of the rough type of algorithm I need: "Exclusive Distance Clustering", one-dimensionally speaking. I did look at what seems to be the popularly referred-to algorithm on this site, the Bin Packing one, but I was unable to see exactly how it would work with my problem. Any help is appreciated. :)

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• C# Accessing controls from an outside class without "public"

  - by Kurt W

  I know this has been asked before but I believe my situation is a bit different -- or I don't understand the answers given. I have spent about 4 hours working on this solidly and finally realized, I just don't know what to do. I have 2 Forms (Form1, Settings) and a class I created called Themes. I have get/set properties that currently work but are all within Form1 and I would like to move as much code related to themeing as I can OUTSIDE of Form1 and into Themes.cs. Changing Theme: To change the theme, the user opens up the Settings form and selects a theme from the dropdown menu and presses the 'Set' button -- this all works, but now I want to move it into my own class and I can't get the code to compile. Here is example code that works before moving -- note that this is only 2 different controls I want to modify but there are about 30 total. I am abridging the code: Form 1: public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void btnSettings_Click(object sender, EventArgs e) { Settings frm = new Settings(this); frm.Show(); } private Color txtRSSURLBGProperty; private Color txtRSSURLFGProperty; public Color TxtRSSURLBGProperty { get { return txtRSSURLBGProperty; } set { txtRSSURL.BackColor = value; } } public Color TxtRSSURLFGProperty { get { return txtRSSURLFGProperty; } set { txtRSSURL.ForeColor = value; } } Settings Form: public partial class Settings : Form { public Settings() { InitializeComponent(); } private Form1 rssReaderMain = null; public Settings(Form requestingForm) { rssReaderMain = requestingForm as Form1; InitializeComponent(); } private void button2_Click(object sender, EventArgs args) { // Appearence settings for DEFAULT THEME if (cbThemeSelect.SelectedIndex == 1) { this.rssReaderMain.TxtRSSURLBGProperty = Color.DarkSeaGreen; this.rssReaderMain.TxtRSSURLFGProperty = Color.White; [......about 25 more of these....] } The theme class is currently empty. Again, the goal is to move as much code into the themes class (specifically the get/set statements if at all possible!) and hopefully just use a method similar to this within the Settings form once the proper drowndown item is selected: SetTheme(Default); I hope someone can help, and I hope I explained it right! I have been racking my brain and I need to have this done fairly soon! Much thanks in advance as I'm sure everyone says. I have teamviewer or logmein if someone wants to remote in -- that is just as easy. I can also send my project as a zip if needed. Thanks so much, Kurt Modified code for review: Form1 form: public partial class Form1 : ThemeableForm { public Form1() { InitializeComponent(); } ThemeableForm form: internal abstract class ThemeableForm : Form { private Color rssLabelBGProperty; private Color rssLabelFGProperty; public Color RssLabelBGProperty { get { return rssLabelBGProperty; } set { lRSS.BackColor = value; } } public Color RssLabelFGProperty { get { return rssLabelFGProperty; } set { lRSS.ForeColor = value; } } Settings form: public Settings(ThemeableForm requestingForm) { rssReaderMain = requestingForm as ThemeableForm; InitializeComponent(); } private ThemeableForm rssReaderMain = null; private void button2_Click(object sender, EventArgs args) { // Appearence settings for DEFAULT THEME if (cbThemeSelect.SelectedIndex == 1) { this.rssReaderMain.LRSSBGProperty = Color.DarkSeaGreen; this.rssReaderMain.LRSSFGProperty = Color.White; } Now the all the controls in my get/set (lRSS in the example code above) error out with does not exist in the current context. I also get the warning: Warning 1The designer could not be shown for this file because none of the classes within it can be designed. The designer inspected the following classes in the file: Form1 --- The base class 'RSSReader_BKRF.ThemeableForm' could not be loaded. Ensure the assembly has been referenced and that all projects have been built. 0 0

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• Installing Windows on HP Proliant Servers without SmartStart

  - by Fitzroy

  I have a PXE server for deploying Windows XP and Windows 7 to workstations. The process is as follows: Boot the workstation from the NIC. Workstation sends a DHCP request. DHCP server responds with an IP address and the location of the PXE server. Workstation downloads WinPE image file from PXE server via TFTP Workstation stores WinPE image file in memory and executes it. Once booted into WinPE, I connect to a network share to gain access to either the Windows XP or Windows 7 installation files. A custom script is launched to guide you through the process of formatting and partitioning the hard drive(s) (using DISKPART and FORMAT). Another custom script asks for details such as the hostname to assign to the workstation. The answers provided are used to build an unattended answer file (SIF [Setup Information File] for WinXP and XML for Win7). The Windows setup EXE is launched, passing the unattended answer file to it as a parameter. The Windows XP and Windows 7 installation sources have been customised to include the drivers for our Dell workstations. They also run a number of scripts upon first booting up to install software packages. This process works very well for our workstations and I would now like to use it for building our servers too. The vast majority of our servers are HP Proliant DL360 G6, DL380 G5 and DL380 G6. They’re running Windows Server 2003 (various editions) or 2008 (various editions). To date, we have always built the HP Proliant servers using the SmartStart CD provided. SmartStart does three useful things for us: Setup RAID with HP Array Configuration Utility (ACU). Installs and configures SNMP Installs various HP Tools for Windows (HP Array Configuration Utility, HP Array Diagnostic Utility, HP Proliant Integrated Management Log Viewer, etc) Using SmartStart I have never had to manually download and install Windows drivers for network, sound, video, etc. I'm not sure if this is because SmartStart copies drivers from the CD during setup, or whether Windows just has the drivers natively in its driver CAB. If I abandon the SmartStart CD in favour of my PXE server I would have to do the following: As I wont have access to ACU, I'll configure the RAID (before booting to the PXE server) by pressing F8 (during the boot process) to access Option ROM Configuration for Arrays (ORCA). Installation of SNMP and the HP Tools will have to be installed once the Windows installation is complete using the Proliant Support Pack. Is this method OK? Is there anything that the SmartStart CD does that I'll be unable to do by other means? Are there any disadvantages to not using the SmartStart CD? Many thanks. UPDATE 05/01/12 I’ve been reading through the SmartStart Scripting Toolkit documentation. The scripting toolkit contains command line tools which work within WinPE and can such things as configure BIOS settings, configure an array and setup ILO. I’m personally not too bothered about configuring BIOS settings as I rarely deviate from the defaults (unless the server is to be a Hyper-V host). I’m not too fussed about being able to configure the array from within WinPE, as I’m happy to just press F8 and use Option ROM Configuration for Arrays (ORCA). Although, if it’s easy enough to do, I will explore this further, as it saves time if everything can be configured from within WinPE. One of the nice features all the tools possess is that you can pass input files to them. EG. Configure one server to your requirements, capture its configuration to a file (using the appropriate tool), you can then use the tool on other servers passing the input file with the captured configuration. Array controller drivers appear to be included with the toolkit along with example of how to incorporate them within a WinPE build. I suppose WinPE won’t be able to see logical volumes (I.E 2x physical disks in a RAID 1 configuration) without the array controller drivers? I mentioned in my post that SmartStart normally installs a bunch of Windows HP tools for you. I’ve had a look today, and if you run the SmartStart CD from within Windows all the tools can be installed. Therefore I can do this after the Windows installation is complete. The SmartStart CD appears to contain a lot Windows drivers. I can customise my Windows 2008 source to incorporate these drivers. However, I understand that incorporating an array controller driver is a little different to most drivers. I believe that you have to provide the driver during the very early stages of the Windows setup. I’m working through the Scripting Toolkit documentation to try and work this out...

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• Remote host: can tracert, can telnet, can*not* browse: what gives?

  - by MacThePenguin

  One of my customers of the company I work for has made a change to their Internet connection, and now we can't connect to them any more from our LAN. To help me troubleshoot this issue, the network guy on the customer's site has configured their firewall so that a HTTPS connection to their public IP address is open to any IP. I should put https://<customer's IP> in my browser and get a web page. Well, it works from any network I've tried (even from my smartphone), just not from my company's LAN. I thought it may be an issue with our firewall (though I checked its rules and it allows outbound TCP port 443 to anywhere), so I just connected a PC directly to the network connection of our provider, bypassing out firewall completely, and still it didn't work (everything else worked). So I asked for help to our Internet provider's customer service, and they asked me to do a tracert to our customer's IP. The tracert is successful, as the final hop shown in the output is the host I want to reach. So they said there's no problem. :( I also tried telnet <customer's IP> 443 and that works as well: I get a blank page with the cursor blinking (I've tried using another random port and that gives me an error message, as it should). Still, from any browser of any PC in my LAN I can't open that URL. I tried checking the network traffic with Wireshark: I see the packages going through and answers coming back, thought the packets I see passing are far less than they are if I successfully connect to another HTTPS website. See the attached screenshot: I had to blur the IPs, anyway the longer string is my PC's local IP address, the shorter one is the customer's public IP. I don't know what else to try. This is the only IP doing this... Any idea what could I try to find a solution to this issue? Thanks, let me know if you need further details. Edit: when I say "it doesn't work" I mean: the page doesn't open, the browser keeps loading for a long time and eventually shows an error saying that the page cannot be opened. I'm not in my office now so I can't paste the exact message, but it's the usual message you get when the browser reaches its timeout. When I say "it works", I mean the browser loads and shows a webpage (it's the logon page for the customers' firewall admin interface: so there's the firewall brand's logo and there are fields to enter a user id and a password). Update 13/09/2012: tried again to connect to the customer's network through our Internet connection without a firewall. This is what I did: Run a Kubuntu 12.04 live distro on a spare laptop; Updated all the packages I could and installed WireShark; Attached it to my LAN and verified that I couldn't open https://<customer's IP>. Verified that the Wireshark trace for this attempt was the same as the one I've already posted; Verified that I could connect to another customer's host using rdesktop (it worked); Tried to rdesktop to <customer's IP>, here's the output: kubuntu@kubuntu:/etc$ rdesktop <customer's IP> Autoselected keyboard map en-us ERROR: recv: Connection reset by peer Disconnected the laptop from the LAN; Disconnected the firewall from the Extranet connection, connected the laptop instead. Set its network configuration so that I could access the Internet; Verified that I could connect to other websites in http and https and in RDP to other customers' hosts - it all worked as expected; Verified that I could still traceroute to <customer's IP>: I could; Verified that I still couldn't open https://<customer's IP> (same exact result as before); Checked the WireShark trace for this attempt and noticed a different behaviour: I could see packets going out to the customer's IP, but no replies at all; Tried to run rdesktop again, with a slightly different result: kubuntu@kubuntu:/etc/network$ rdesktop <customer's IP> Autoselected keyboard map en-us ERROR: <customer's IP>: unable to connect Finally gave up, put everything back as it was before, turned off the laptop and lost the WireShark traces I had saved. :( I still remember them very well though. :) Can you get anything out of it? Thank you very much. Update 12/09/2012 n.2: I followed the suggestion by MadHatter in the comments. From inside the firewall, this is what I get: user@ubuntu-mantis:~$ openssl s_client -connect <customer's IP>:443 CONNECTED(00000003) If I now type GET / the output pauses for several seconds and then I get: write:errno=104 I'm going to try the same, but bypassing the firewall, as soon as I can. Thanks. Update 12/09/2012 n.3: So, I think ISA Server is altering the results of my tests... I tried installing Wireshark directly on the firewall and monitoring the packets on the Extranet network card. When the destination is the customer's IP, whatever service I try to connect to (HTTPS, RDP or SAProuter), I can only see outbound packets and no response packets whatsoever from their side. It looks like ISA Server is "faking" the remote server's replies, that's why I get a connection using telnet or the openSSL client. This is the wireshark trace from inside our LAN: But this is the trace on the Extranet network card: This makes a bit more sense... I'll send this info to the customer's tech and see if he can make anything out of it. Thanks to all that took the time to read my question and post suggestions. I'll update this post again.

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• Have suggestions for these assembly mnemonics?

  - by Noctis Skytower

  Greetings! Last semester in college, my teacher in the Computer Languages class taught us the esoteric language named Whitespace. In the interest of learning the language better with a very busy schedule (midterms), I wrote an interpreter and assembler in Python. An assembly language was designed to facilitate writing programs easily, and a sample program was written with the given assembly mnemonics. Now that it is summer, a new project has begun with the objective being to rewrite the interpreter and assembler for Whitespace 0.3, with further developments coming afterwards. Since there is so much extra time than before to work on its design, you are presented here with an outline that provides a revised set of mnemonics for the assembly language. This post is marked as a wiki for their discussion. Have you ever had any experience with assembly languages in the past? Were there some instructions that you thought should have been renamed to something different? Did you find yourself thinking outside the box and with a different paradigm than in which the mnemonics were named? If you can answer yes to any of those questions, you are most welcome here. Subjective answers are appreciated! Stack Manipulation (IMP: [Space]) Stack manipulation is one of the more common operations, hence the shortness of the IMP [Space]. There are four stack instructions. hold N Push the number onto the stack copy Duplicate the top item on the stack copy N Copy the nth item on the stack (given by the argument) onto the top of the stack swap Swap the top two items on the stack drop Discard the top item on the stack drop N Slide n items off the stack, keeping the top item Arithmetic (IMP: [Tab][Space]) Arithmetic commands operate on the top two items on the stack, and replace them with the result of the operation. The first item pushed is considered to be left of the operator. add Addition sub Subtraction mul Multiplication div Integer Division mod Modulo Heap Access (IMP: [Tab][Tab]) Heap access commands look at the stack to find the address of items to be stored or retrieved. To store an item, push the address then the value and run the store command. To retrieve an item, push the address and run the retrieve command, which will place the value stored in the location at the top of the stack. save Store load Retrieve Flow Control (IMP: [LF]) Flow control operations are also common. Subroutines are marked by labels, as well as the targets of conditional and unconditional jumps, by which loops can be implemented. Programs must be ended by means of [LF][LF][LF] so that the interpreter can exit cleanly. L: Mark a location in the program call L Call a subroutine goto L Jump unconditionally to a label if=0 L Jump to a label if the top of the stack is zero if<0 L Jump to a label if the top of the stack is negative return End a subroutine and transfer control back to the caller halt End the program I/O (IMP: [Tab][LF]) Finally, we need to be able to interact with the user. There are IO instructions for reading and writing numbers and individual characters. With these, string manipulation routines can be written. The read instructions take the heap address in which to store the result from the top of the stack. print chr Output the character at the top of the stack print int Output the number at the top of the stack input chr Read a character and place it in the location given by the top of the stack input int Read a number and place it in the location given by the top of the stack Question: How would you redesign, rewrite, or rename the previous mnemonics and for what reasons?

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