Search Results

Search found 2911 results on 117 pages for 'restore'.

Page 103/117 | < Previous Page | 99 100 101 102 103 104 105 106 107 108 109 110  | Next Page >

• Silverlight Cream for February 04, 2011 -- #1040

  - by Dave Campbell

  In this Issue: Shawn Wildermuth, John Papa, Jesse Liberty(-2-), Mike Wolf, Matt Casto, Levente Mihály, Roy Dallal, Mark Monster, Andrea Boschin, and Oren Gal. Above the Fold: Silverlight: "Accept and Cancel Buttons Behavior in Silverlight" Matt Casto WP7: "Windows Phone 7 Runtime Debugging" Mike Wolf Shoutouts: Al Pascual announced a get-together if you're going to be in Phoenix on February 10 (next Thursday)... I just can't tell what time it is from the page: Phoenix Dev Meet-Up From SilverlightCream.com: Ten Pet Peeves of WP7 Applications Check out Shawn Wildermuth's Top 10 annoyances when trying out any new app on the WP7... if you're a dev, you might want to keep these in mind. Silverlight TV 60: Checking Out the Zero Gravity Game, Now on Windows Phone 7 John Papa has Silverlight TV number 60 up and this one features Phoenix' own Ryan Plemons discussing the game Zero Gravity and some of the things he had to do to take the game to WP7 ... and the presentation looks as good from here as it did inside the studio :) The Full Stack: Entity Framework To Phone, The Server Side Jesse Liberty and Jon Galloway have Part 6 of their full-stack podcast up ... this is their exploration of MVC3, ASP.NET, Silverlight, and WP7... pair programming indeed! Life Cycle: Page State Management Jesse Liberty also has episode 29 (can you believe that??) of his Windows Phone From Scratch series up ... he's continuing his previous LifeCycle discussion with Page State Management this time. Windows Phone 7 Runtime Debugging Mike Wolf is one of those guys that when he blogs, we should all pay attention, and this post is no exception... he has contributed a run-time diagnostics logger to the WP7Contrib project ... wow... too cool! Accept and Cancel Buttons Behavior in Silverlight Matt Casto has his blog back up and has a behavior up some intuitive UX on ChildWindows by being able to bind to a default or cancel button and have those events activated when the user hits Enter or Escape... very cool, Matt! A classic memory game: Part 3 - Porting the game to Windows Phone 7 Levente Mihály has Part 3 of his tutorial series up at SilverlightShow, and this go-around is porting his 'memory game' to WP7... and this is pretty all-encompassing... Blend for the UI, Performance, and Tombstoning... plus all the source. Silverlight Memory Leak, Part 1 Roy Dallal completely describes how he used a couple easily-downloadable tools to find the root cause of his memory problems with is Silvleright app. Lots of good investigative information. How to cancel the closing of your Silverlight application (in-browser and out-of-browser) Mark Monster revisits a two-year old post of his on cancelling the closing of a Silverlight app... and he's bringing that concept of warning the user the he's about to exit into the OOB situation as well. Windows Phone 7 - Part #3: Understanding navigation Also continuing his WP7 tutorial series on SilverlightShow, Andrea Boschin has part 3 up which is all about Navigation and preserving state... he also has a video on the page to help demonstrate the GoBack method. Multiple page printing in Silverlight 4 Oren Gal built a Silverlight app for last years' ESRI dev summit, and decided to upgrade it this year with functionality such as save/restore, selecting favorite sessions, and printing. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

  Read the article

• Steps for MySQL DB Replication

  - by Manish Agrawal

  Following are the steps for MySQL Replication implementation on Linux machine: Pre-implementation steps for DB Replication:   1.    Identify the databases to be replicated 2.    Identify the tables to be ignored during replication per database for example log tables 3.  Carefully identify and replace the variables and paths(locations) mentioned (in bold) in the commands given below with appropriate values 4.  Schedule the maintenance activity in odd hours as these activities will affect all the databases on Master database server       Implementation steps for DB Replication:     1.    Configure the /etc/my.cnf file on Master database server to enable Binary logging, setting of server id and configuring of dbnames for which logging should be done. [mysqld] log-bin=mysql-bin server-id=1 binlog-do-db = dbname   Note: You can specify multiple DB in binlog-do-db by using comma separated dbname values like: dbname1, dbname2, …, dbnameN   2.    On Master database, Grant Replication Slave Privileges, by executing following command on mysql prompt mysql> GRANT REPLICATION SLAVE ON *.* TO slaveuser@<hostname> identified by ‘slavepassword’;   3.    Stop the Master & Slave database by giving the command      mysqladmin shutdown   4.    Start the Master database by giving the command      /usr/local/mysql-5.0.22/bin/mysqld_safe --user=user&     5.    mysql> FLUSH TABLES WITH READ LOCK; Note: Leave the client (putty session) from which you issued the FLUSH TABLES statement running, so that the read lock remains in effect. If you exit the client, the lock is released. 6.    mysql > SHOW MASTER STATUS;          +---------------+----------+--------------+------------------+          | File          | Position | Binlog_Do_DB | Binlog_Ignore_DB |          +---------------+----------+--------------+------------------+          | mysql-bin.003 | 117       | dbname       |                  |          +---------------+----------+--------------+------------------+ Note: Note this information as this will be required while starting of Slave and replication in later steps   7.    Take MySQL dump by giving the following command, In another session window (putty window) run the following command: mysqldump –u user --ignore-table=dbname.tbl_name -–ignore-table=dbname.tbl_name2 --master-data dbname > dbname_dump.db Note: When choosing databases to include in the dump, remember that you will need to filter out databases on each slave that you do not want to include in the replication process.     8.    Unlock the tables on Master by giving following command: mysql> UNLOCK TABLES;   9.    Copy the dump file to Slave DB server   10.  Startup the Slave by using option --skip-slave      /usr/local/mysql-5.0.22/bin/mysqld_safe --user=user --skip-slave&   11.  Restore the dump file on Slave DB server      mysql –u user dbname < dbname_dump.db   12.  Stop the Slave database by giving the command      mysqladmin shutdown   13.  Configure the /etc/my.cnf file on the Slave database server [mysqld] server-id=2 replicate-ignore-table = dbname.tablename   14.  Start the Slave Mysql Server with 'replicate-do-db=DB name' option.      /usr/local/mysql-5.0.22/bin/mysqld_safe --user=user --replicate-do-db=dbname --skip-slave   15.  Configure the settings at Slave server for Master host name, log filename and position within the log file as shown in Step 6 above Use Change Master statement in the MySQL session mysql> CHANGE MASTER TO MASTER_HOST='<master_host_name>', MASTER_USER='<replication_user_name>', MASTER_PASSWORD='<replication_password>', MASTER_LOG_FILE='<recorded_log_file_name>', MASTER_LOG_POS=<recorded_log_position>;   16.  On Slave Servers mysql prompt give the following command: a.     mysql > START SLAVE; b.    mysql > SHOW SLAVE STATUS;         Note: To stop slave for backup or any other activity you can use the following command on the Slave Servers mysql prompt: mysql> STOP SLAVE     Refer following links for more information on MySQL DB Replication: http://dev.mysql.com/doc/refman/5.0/en/replication-options.html http://crazytoon.com/2008/04/21/mysql-replication-replicate-by-choice/ http://dev.mysql.com/doc/refman/5.0/en/mysqldump.html

  Read the article

• Few events I&rsquo;m speaking at in early 2013

  - by Mladen Prajdic

  2013 has started great and the SQL community is already brimming with events. At some of these events you can come say hi. I’ll be glad you do! These are the events with dates and locations that I know I’ll be speaking at so far.   February 16th: SQL Saturday #198 - Vancouver, Canada The session I’ll present in Vancouver is SQL Impossible: Restoring/Undeleting a table Yes, you read the title right. No, it's not about the usual "one table per partition" and "restore full backup then copy the data over" methods. No, there are no 3rd party tools involved. Just you and your SQL Server. Yes, it's crazy. No, it's not for production purposes. And yes, that's why it's so much fun. Prepare to dive into the world of data pages, log records, deletes, truncates and backups and how it all works together to get your table back from the endless void. Want to know more? Come and see! This is an advanced level session where we’ll dive into the internals of data pages, transaction log records and page restores.   March 8th-9th: SQL Saturday #194 - Exeter, UK In Exeter I’ll be presenting twice. On the first day I’ll have a full day precon titled: From SQL Traces to Extended Events - The next big switch This pre-con will give you insight into both of the current tracing technologies in SQL Server. The old SQL Trace which has served us well over the past 10 or so years is on its way out because the overhead and details it produces are no longer enough to deal with today's loads. The new Extended Events are a new lightweight tracing mechanism built directly into the SQLOS thus giving us information SQL Trace just couldn't. They were designed and built with performance in mind and it shows. The new Extended Events are a new lightweight tracing mechanism built directly into the SQLOS thus giving us information SQL Trace just couldn't. They were designed and built with performance in mind and it shows. Mastering Extended Events requires learning at least one new skill: XML querying. The second session I’ll have on Saturday titled: SQL Injection from website to SQL Server SQL Injection is still one of the biggest reasons various websites and applications get hacked. The solution as everyone tells us is simple. Use SQL parameters. But is that enough? In this session we'll look at how would an attacker go about using SQL Injection to gain access to your database, see its schema and data, take over the server, upload files and do various other mischief on your domain. This is a fun session that always brings out a few laughs in the audience because they didn’t realize what can be done.   April 23rd-25th: NTK conference - Bled, Slovenia (Slovenian website only) This is a conference with history. This year marks its 18th year running. It’s a relatively large IT conference that focuses on various Microsoft technologies like .Net, Azure, SQL Server, Exchange, Security, etc… The main session’s language is Slovenian but this is slowly changing so it’s becoming more interesting for foreign attendees. This year it’s happening in the beautiful town of Bled in the Alps. The scenery alone is worth the visit, wouldn’t you agree? And this year there are quite a few well known speakers present! Session title isn’t known yet.       May 2nd-4th: SQL Bits XI – Nottingham, UK SQL Bits is the largest SQL Server conference in Europe. It’s a 3 day conference with top speakers and content all dedicated to SQL Server. The session I’ll present here is an hour long version of the precon I’ll give in Exeter. From SQL Traces to Extended Events - The next big switch The session description is the same as for the Exeter precon but we'll focus more on how the Extended Events work with only a brief overview of old SQL Trace architecture.

  Read the article

• MIXing it Up a Bit

  - by andrewbrust

  Another March, another MIX.  For the fifth year running now, Microsoft has chosen to put on a conference aimed less at software development, per se, and more at the products, experiences and designs that software development can generate.  In all four prior MIX events, the focus of the show, its keynotes and breakout sessions has been on Web products.  On day 1 of MIX 2010 that focus shifted to Windows Phone 7 Series (WP7). What little we had seen of WP7 had been shown to us in a keynote presentation, given by Microsoft’s Joe Belfiore, at the Mobile World Congress in Barcelona, Spain last month.  And today, Mr. Belfiore reprised his showmanship for the MIX 2010 audience.  Joe showed us the ins and outs of WP7 and, in a breakout session, even gave us a sneak peek of Office (specifically, Excel) on WP7.  We didn’t get to see that one month ago in Barcelona, nor did get to see email messages opened for reading, which we saw today. But beyond a tour of the phone itself, impressive though that is, we got to see apps running on it.  Those apps included Associated Press news, Seesmic (a major Twitter client) and Foursquare (a social media darling).  All three ran, ran well, and looked markedly different and better from their corresponding versions on iPhone and Android.  And the games we saw looked even better. To me though, the best demos involved the creation of WP7 apps, using Silverlight in Visual Studio and Expression Blend.  These demos were so effective because they showed important apps being built in very few steps, and by Microsoft executives to boot.  Scott Guthrie showed us how to build a Twitter API app in Visual Strudio.   Jon Harris showed us how to build a photo management and viewer application in Expression Blend, using virtually no code.  Demos of apps built from scratch to F5 without the benefit of a teacher, could be challenging.  But they went off fine, without a hitch and without a ton of opaque, generated code.  Everything written, be it C# or XAML, was easily understood, and the results were impressive. That means lots of developers can do this, and I think it means a lot will.  What I’ve seen, thus far, of iPhone and Android development looks very tedious by comparison.  Development for those platforms involve a collection of tools that integrate only to a point.  Dev work for WP7 involves use of Visual Studio, Silverlight and the same debugging experience .NET developers already know.  This was very exciting for me. All the demos harkened back to days of building apps for with Visual Basic…design the front-end, put in code-behind and then hit F5.  And that makes sense, because the phone platform, and the PC of the early 90s are both, essentially, client OS machines.  The Web was minimal and the “device” was everything. Same is true of this phone.  It’s a client app contraption that fits in your pocket. And if the platforms are comparable, hopefully so too will be the draw of ease-of-development.   WP7 has the potential to make mobile developers want to switch over, and to convince enterprise developers to get into the phone scene.  Will this propel the new phone platform to new heights, and restore Microsoft’s competiveness in the mobile arena? I hope so.  I think so.  And if Microsoft uses developers to build themselves a victory, that would be beneficial and would show that Microsoft has learned from its failures, as well as its successes.  Today I saw a few beautiful apps.  Tomorrow I hope I see a slew of others; maybe not as polished, but plentiful, attractive and stable.  That would be a victory for Microsoft, and for developers.  And it would show everyone else that developers are the kingmakers.  They need cheap, efficient dev tools and lots of respect.  Microsoft has always been the company to provide that.  Hopefully, with WP7, they will return to that persona and see how very timeless it is.

  Read the article

• PASS Summit 2011 &ndash; Part IV

  - by Tara Kizer

  This is the final blog for my PASS Summit 2011 series.  Well okay, a mini-series, I guess. On the last day of the conference, I attended Keith Elmore’ and Boris Baryshnikov’s (both from Microsoft) “Introducing the Microsoft SQL Server Code Named “Denali” Performance Dashboard Reports, Jeremiah Peschka’s (blog|twitter) “Rewrite your T-SQL for Great Good!”, and Kimberly Tripp’s (blog|twitter) “Isolated Disasters in VLDBs”. Keith and Boris talked about the lifecycle of a session, figuring out the running time and the waiting time.  They pointed out the transient nature of the reports.  You could be drilling into it to uncover a problem, but the session may have ended by the time you’ve drilled all of the way down.  Also, the reports are for troubleshooting live problems and not historical ones.  You can use Management Data Warehouse for historical troubleshooting.  The reports provide similar benefits to the Activity Monitor, however Activity Monitor doesn’t provide context sensitive drill through. One thing I learned in Keith’s and Boris’ session was that the buffer cache hit ratio should really never be below 87% due to the read-ahead mechanism in SQL Server.  When a page is read, it will read the entire extent.  So for every page read, you get 7 more read.  If you need any of those 7 extra pages, well they are already in cache.  I had a lot of fun in Jeremiah’s session about refactoring code plus I learned a lot.  His slides were visually presented in a fun way, which just made for a more upbeat presentation.  Jeremiah says that before you start refactoring, you should look at your system.  Investigate missing or too many indexes, out-of-date statistics, and other areas that could be leading to your code running slow.  He talked about code standards.  He suggested using common abbreviations for aliases instead of one-letter aliases.  I’m a big offender of one-letter aliases, but he makes a good point.  He said that join order does not matter to the optimizer, but it does matter to those who have to read your code.  Now let’s get into refactoring! Eliminate useless things – useless/unneeded joins and columns.  If you don’t need it, get rid of it! Instead of using DISTINCT/JOIN, replace with EXISTS Simplify your conditions; use UNION or better yet UNION ALL instead of OR to avoid a scan and use indexes for each union query Branching logic – instead of IF this, IF that, and on and on…use dynamic SQL (sp_executesql, please!) or use a parameterized query in the application Correlated subqueries – YUCK! Replace with a join Eliminate repeated patterns Last, but certainly not least, was Kimberly’s session.  Kimberly is my favorite speaker.  I attended her two-day pre-conference seminar at PASS Summit 2005 as well as a SQL Immersion Event last December.  Did I mention she’s my favorite speaker?  Okay, enough of that. Kimberly’s session was packed with demos.  I had seen some of it in the SQL Immersion Event, but it was very nice to get a refresher on these, especially since I’ve got a VLDB with some growing pains.  One key takeaway from her session is the idea to use a log shipping solution with a load delay, such as 6, 8, or 24 hours behind the primary.  In the case of say an accidentally dropped table in a VLDB, we could retrieve it from the secondary database rather than waiting an eternity for a restore to complete.  Kimberly let us know that in SQL Server 2012 (it finally has a name!), online rebuilds are supported even if there are LOB columns in your table.  This will simplify custom code that intelligently figures out if an online rebuild is possible. There was actually one last time slot for sessions that day, but I had an airplane to catch and my kids to see!

  Read the article

• Using the SOA-BPM VIrtualBox Appliance

  - by antony.reynolds

  Quickstart Guide to Using Oracle Appliance for SOA/BPM Recently I have been setting up some machines for fellow engineers.  My base setup consists of Oracle Enterprise Linux with Oracle Virtual Box.  Note that after installing VirtualBox I needed to add the VirtualBox Extension Pack to enable RDP access amongst other features.  In order to get them started quickly with some images I downloaded the pre-built appliance for SOA/BPM from OTN. Out of the box this provides a VirtualBox image that is pre-installed with everything you will need to develop SOA/BPM applications. Specifically by using the virtual appliance I got the following pre-installed and configured. Oracle Enterprise Linux 5 User oracle password oracle User root password oracle. Oracle Database XE Pre-configured with SOA/BPM repository. Set to auto-start on OS startup. Oracle SOA Suite 11g PS2 Configured with a “collapsed domain”, all services (SOA/BAM/EM) running in AdminServer. Listening on port 7001 Oracle BPM Suite 11g Configured in same domain as SOA Suite. Oracle JDeveloper 11g With SOA/BPM extensions. Networking The VM by default uses NAT (Network Address Translation) for network access.  Make sure that the advanced settings for port forwarding allow access through the host to guest ports.  It should be pre-configured to forward requests on the following ports Purpose Host Port Guest Port (VBox Image) SSH 2222 22 HTTP 7001 7001 Database 1521 1521 Note that only one VirtualBox image can use a given host port, so make sure you are not clashing if it seems not to work. What’s Left to Do? There is still some customization of the environment that may be required. If you need to configure a proxy server as I did then for the oracle and root users to set up an HTTP proxy Added “export http_proxy=http://proxy-host:proxy-port” to ~oracle/.bash_profile and ~root/.bash_profile Added “export http_proxy=http://proxy-host:proxy-port” to /etc/.bashrc Edited System->Preferences to set Network Proxy In Firefox set Preferences->Network->Connection Settings to “Use system proxy settings” In JDeveloper set Edit->Preferences->Web Browser and Proxy to required proxy settings You may need to configure yum to point to a public OEL yum repository – such as http://public-yum.oracle.com. If you are going to be accessing the SOA server from outside the VirtualBox image then you may want to set the soa-infra Server URLs to be the hostname of the host OS. Snap! Once I had the machine configured how I wanted to use it I took a snapshot so that I can always get back to the pristine install I have now.  Snapshots are one of the big benefits of putting a development environment into a virtualized environment.  I can make changes to my installation and if I mess it up I can restore the image to a last known good snapshot. Hey Presto!, Ready to Go This is the quickest way to get up and running with SOA/BPM Suite.  Out of the box the download will work, I only did extra customization so I could use services outside the firewall and browse outside the firewall from within by SOA VirtualBox image.  I also use yum to update the OS to the latest binaries. So have fun.

  Read the article

• Sorry about the wait.

  - by Ratman21

  In the last two days have been trying remove “Iolo System Mechanic Professional” (With anti-virus and FireWall) from 3 of the 5 pc’s we have (3 lap tops and two Desk tops) as it was going to expire on the 13th.   So I could replace them with a free anti-virus (AVG) and just use the windows fire wall. I have been using the same set up on one of my desk tops (XP Pro) for 8 months and one of the Lap tops (Vista) for 5 months.   The problem was that System Mechanic did not want to go. Even after using the uninstall option on the desk top (my main PC, well its that because has the larger of all the PC’s hard drives but, is the oldest and runs XP home) and using Ccleaner to try and remove it.  It was still showing up as there and after I went a head and tried installing AVG and ran it. I found that the TCP/IP module was missing.  So no internet, I had to restore the PC back to the 1st to get the module back and then install AVG (after making sure window firewall was back on. I didn’t check that on the first try). Got the PC back to normal, very late last night. Only one of the two lap tops was easy but, even at that there are still some parts of System Mechanic on it but, AVG and firewall are working.   I may try an hunt down parts of System Mechanic on it and delete them on this lap top. Which was what finally had to do on the one of the Lap tops (also XP Home) as it would not uninstall after I restored the PC back to the 4th. So delete, delete, delete and Ccleaner (one dl file would not delete though). And I just finish installing AVG and now running a scan on the lap top. So all of this took two days (well three counting today). I started late Friday night and just finishing up now.   I only started this switch over after I had finished my Job search for day on Friday.   As for blogging on Tuesday, Wednesday and Thursday, I was busy and by the end of the day was too tired to blog, that and was hung up still on that 2nd dare of The Love Dare. So I cleaned the house, while she was out of the house. I mean, I cleaned, not just vacuumed house I cleaned the kitchen counter tops and the sinks. Did the dishes and some of the laundry over two of the those days.   As to the third day of Love Dare which is “Love is not selfish” and the dare “Whatever you put your time, energy, and money into will become more important to you. It’s hard to care for something you are not investing in. Along with restraining from negative comments, buy your spouse something that says, I was thinking of you today.”   Being on a very limited income, a lot of normal guy buying for girls is out (for one thing, the comment why did you waste our money on flowers, etc, etc, would come up. Not from me though). So that one is on hold till money issues are not a problem (no that does not mean never). The 4th day “Love is thoughtful” and the dare “Contact your spouse sometime during the business of the day. Have no agenda other than asking how he or she is doing and if there is anything you could do for them”.   I did this dare while I was still working with census last week and trying to do the dares. Well I start my CCNA classes Monday the 15th and I move on to the next Love Dare day “Love is not rude”.

  Read the article

• Customize SharePoint list using InfoPath2010 form Part4

  - by ybbest

  Customize SharePoint list using InfoPath2010 form Part1 Customize SharePoint list using InfoPath2010 form Part2 Customize SharePoint list using InfoPath2010 form Part3 In this post, I’d like to show you how to create print functionality in InfoPath for SharePoint list. The print functionality is provided out of box in InfoPath form library; however it is not available in SharePoint list. Here are the steps to create the print functionality.You can download the new form here. 1. Create print page in the list by first copy and paste the displayifs.aspx and rename the file to Printifs.aspx. 2. Open the page in the SharePoint designer and copy the following javascript to the PlaceHolderTitleAreaClass ContentPlaceHolder. <script type="text/javascript"> $(document).ready(function(){ $("[id^='Ribbon']").hide(); $(".s4-title").hide(); $("[id='s4-leftpanel']").hide(); $("[id='s4-ribbonrow']").hide(); $("[id='s4-titlerow']").hide(); $("[id='s4-titlerow']").css("height", "0px"); $("body").css("background-color", "white"); $("body").css("zoom", "135%"); $("[id='MSO_ContentTable']").css("margin-left", "0px"); $("[id='MT-BodyContent']").css("width", "900px"); $(".MT-BodyArea").css("width", "900px"); $("[id='MT-Layout']").css("width", "900px"); $(".ms-bodyareacell").css("width", "900px"); $(".s4-wpTopTable").css("border", "none"); $("[id$='XmlFormView']").css("margin-left", "-80px"); $("body").css("margin-top", "-30px"); $(":contains('CAPEX')").css("border", "5px solid #FFCC00"); window.print(); }); </script> 3. Open InfoPath form for the list and create a field called PrintLink 4. Set the default value of printLink that points to the print page I just created before with the query string id.You can download the formula for the default value here. 5. Add a new image that looks like Print button on the display view, then I can set the url to the Print link Field. (The reason I did not use button is that you cannot set the navigate url for the button). 6.Set the url of the image to the PrintLInk field. 7.Next , create the print view. 8. Copy the contents from the display view to print view 9. Finally, go to the printifs.aspx and edit the InfoPath web part to set the view to PrintView. 9. Republish you form you will see the form as shown below 10. If you click the Print button, you will see the print page and print dialog,you can also add the company logo in the print page using css as well. 11.To deploy the customization,you can use the backup and restore content database approach , you can get more details from my previous blog post here.

  Read the article

• no launcher, no dash, no unity, how to get back to my desktop?

  - by Numan Syed

  FYI, I have tried these, but none worked as of yet! Please help! I must not want to reinstall Ubuntu precise: AskUbuntu:Unity Launcher missing AskUbuntu: Unity doesn't load Youtube:Restore missing launcher AskUbuntu:Unity 3D no longer works! Is there any other way to find a solution, any help is highly appreciated! Please do ask for any further info u may need to point me to a better direction. Edit: I have still the opportunity to use ctrl+Alt+T for the terminal. And from there I used firefox & to get the browser on. Edit 2: Tried to find more; found more explained situation http://askubuntu.com/q/260578/176470. Edit 3:@Adithya: tried that no luck! Here is what my terminal gave me so far... [1447:22] (~) bash $ unity --reset WARNING: Unity currently default profile, so switching to metacity while resetting the values unity-panel-service: no process found Checking if settings need to be migrated ...no Checking if internal files need to be migrated ...no Backend : gconf Integration : true Profile : unity Adding plugins Initializing core options...done compiz (core) - Warn: failed to receive ConfigureNotify event on 0x1600004 compiz (core) - Warn: failed to receive ConfigureNotify event on 0x30000b8 compiz (core) - Warn: failed to receive ConfigureNotify event on 0x2c00fc1 Initializing composite options...done Initializing opengl options...done Initializing decor options...done Initializing vpswitch options...done Initializing snap options...done Initializing mousepoll options...done Initializing resize options...done Initializing place options...done Initializing move options...done Initializing wall options...done Initializing grid options...done Initializing session options...done Initializing gnomecompat options...done Initializing animation options...done Initializing fade options...done compiz (core) - Error: Couldn't load plugin '/usr/lib/compiz/libunitymtgrabhandles.so' : /usr/lib/compiz/libunitymtgrabhandles.so: undefined symbol: _ZN10CompOption7setNameEPKcNS_4TypeE compiz (core) - Error: Couldn't load plugin 'unitymtgrabhandles' Initializing workarounds options...done Initializing scale options...done compiz (expo) - Warn: failed to bind image to texture Initializing expo options...done Initializing ezoom options...done compiz (core) - Error: Couldn't load plugin '/usr/lib/compiz/libunityshell.so' : /usr/lib/compiz/libunityshell.so: undefined symbol: _ZN10CompOption7setNameEPKcNS_4TypeE compiz (core) - Error: Couldn't load plugin 'unityshell' compiz (core) - Warn: unhandled ConfigureNotify on 0xc000a0! compiz (core) - Warn: this should never happen. you should probably file a bug about this. compiz (core) - Warn: unhandled ConfigureNotify on 0xc000a3! compiz (core) - Warn: this should never happen. you should probably file a bug about this. compiz (core) - Warn: unhandled ConfigureNotify on 0xc000a6! compiz (core) - Warn: this should never happen. you should probably file a bug about this. Initializing addhelper options...done Initializing animationaddon options...done Initializing annotate options...done Initializing bench options...done Initializing blur options...done Initializing clone options...done Initializing colorfilter options...done Initializing commands options...done Initializing crashhandler options...done Initializing cube options...done Initializing cubeaddon options...done Initializing extrawm options...done Initializing fadedesktop options...done Initializing firepaint options...done Initializing group options...done Initializing imgjpeg options...done Initializing kdecompat options...done Initializing loginout options...done Initializing mag options...done Initializing maximumize options...done Initializing mblur options...done Initializing neg options...done Initializing notification options...done Initializing obs options...done Initializing opacify options...done Initializing put options...done Initializing reflex options...done Initializing resizeinfo options...done Initializing ring options...done Initializing rotate options...done Initializing scaleaddon options...done Initializing scalefilter options...done Initializing screenshot options...done Initializing shelf options...done Initializing shift options...done Initializing showdesktop options...done Initializing showmouse options...done Initializing splash options...done Initializing staticswitcher options...done Initializing switcher options...done Initializing td options...done Initializing thumbnail options...done Initializing trailfocus options...done Initializing unitymtgrabhandles options...done Initializing unityshell options...done Initializing wallpaper options...done Initializing water options...done Initializing widget options...done Initializing winrules options...done Initializing wobbly options...done Setting Update "main_menu_key" Setting Update "run_key" Anything suspicious herein?

  Read the article

• Performing an upgrade from TFS 2008 to TFS 2010

  - by Enrique Lima

  I recently had to go through the process of migrating a TFS 2008 SP1 to a TFS 2010 environment. I will go into the details of the tasks that I went through, but first I want to explain why I define it as a migration and not an upgrade. When this environment was setup, based on support and limitations for TFS 2008, we used a 32 bit platform for the TFS Application Tier and Build Servers.  The Data Tier, since we were installing SP1 for TFS 2008, was done as a 64 bit installation.  We knew at that point that TFS 2010 was in the picture so that served as further motivation to make that a 64bit install of SQL Server.  The SQL Server at that point was a single instance (Default) installation too.  We had a pretty good strategy in place for backups of the databases supporting the environment (and this made the migration so much smoother), so we were pretty familiar with the databases and the purpose they serve. I am sure many of you that have gone through a TFS 2008 installation have encountered challenges and trials.  And likely even more so if you, like me, needed to configure your deployment for SSL.  So, frankly I was a little concerned about the process of migrating.  They say practice makes perfect, and this environment I worked on is in some way my brain child, so I was not ready nor willing for this to be a failure or something that would impact my client’s work. Prior to going through the migration process, we did the install of the environment.  The Data Tier was the same, with a new Named instance in place to host the 2010 install.  The Application Tier was in place too, and we did the DefaultCollection configuration to test and validate all components were in place as they should. Anyway, on to the tasks for the migration (thanks to Martin Hinselwood for his very thorough documentation): Close access to TFS 2008, you want to make sure all code is checked in and ready to go.  We stated a difference of 8 hours between code lock and the start of migration to give time for any unexpected delay.  How do we close access?  Stop IIS. Backup your databases.  Which ones? TfsActivityLogging TfsBuild TfsIntegration TfsVersionControl TfsWorkItemTracking TfsWorkItemTrackingAttachments Restore the databases to the new Named Instance (make sure you keep the same names) Now comes the fun part! The actual import/migration of the databases.  A couple of things happen here. The TfsIntegration database will be scanned, the other databases will be checked to validate they exist.  Those databases will go through a process of data being extracted and transferred to the TfsVersionControl database to then be renamed to Tfs_<Collection>. You will be using a tool called tfsconfig and the option import. This tool is located in the TFS 2010 installation path (C:\Program Files\Microsoft Team Foundation Server 2010\Tools),  the command to use is as follows:    tfsconfig import /sqlinstance:<instance> /collectionName:<name> /confirmed Where <instance> is going to be the SQL Server instance where you restored the databases to.  <name> is the name you will give the collection. And to explain /confirmed, well this means you have done a backup of the databases, why?  well remember you are going to merge the databases you restored when you execute the tfsconfig import command. The process will go through about 200 tasks, once it completes go to Team Foundation Server Administration Console and validate your imported databases and contents. We’ll keep this manageable, so the next post is about how to complete that implementation with the SSL configuration.

  Read the article

• DAC pack up all your troubles

  - by Tony Davis

  Visual Studio 2010, or perhaps its apparently-forthcoming sister, "SQL Studio", is being geared up to become the natural way for developers to create databases. Central to this drive is the introduction of 'data-tier application components', or DACs. Applications are developed as normal but when it comes to deployment, instead of supplying the DBA with a bunch of scripts to create the required database objects, the developer creates a single DAC Package ("DAC Pack"); a zipped XML file containing all the database objects needed by the application, along with versioning information, policies for deployment, and so on. It's an intriguing prospect. Developers can work on their development database using their existing tools and source control, and then package up the changes into a single DACPAC for deployment and management. DBAs get an "application level view" of how their instances are being used and the ability to collectively, rather than individually, manage the objects. The DBA needing to manage a large number of relatively small databases can use "DAC snapshots" to get a quick overview of what has changed across all the databases they manage. The reason that DAC packs haven't caused more excitement is that they can only be pushed to SQL Server 2008 R2, and they must be developed or inspected using Visual Studio 2010. Furthermore, what we see right now in VS2010 is more of a 'work-in-progress' or 'vision of the future', with serious shortcomings and restrictions that render it unsuitable for anything but small 'non-critical' departmental databases. The first problem is that DAC packs support a limited set of schema objects (corresponding closely to the features available on 'Azure'). This means that Service Broker queues, CLR Objects, and perhaps most critically security (permissions, certificates etc.), are off-limits. Applications that require these objects will need to add them via a post-deployment TSQL script, rather defeating the whole idea. More worrying still is the process for altering a database with a DAC pack. The grand 'collective' philosophy, whereby a single XML file can be used for deploying and managing builds and changes, extends, unfortunately, to database upgrades. Any change to a database object will result in the creation of a new database, copying the data from the old version, nuking the previous one, and then renaming the new one. Simple eh? The problem is that even something as trivial as adding a comment to a stored procedure in a 5GB database will require the server to find at least twice as much space, as well sufficient elbow-room in the transaction log for copying the largest table. Of course, you'll need to take the database offline for the full course of the deployment, which is likely to take a long time if there is a lot of data. This upgrade/rename process breaks the log chain, makes any subsequent full restore operation highly complicated, and will also break log shipping. As with any grand vision, the devil is always in the detail. It's hard to fathom why Microsoft hasn't used a SQL Compare-style approach to the upgrade process, altering a database with a change script, and this will surely be adopted in the near future. Something had to be in place for VS2010, but right now DAC packs only make sense for Azure. For this, they're cute, but hardly compelling. Nevertheless, DBAs would do well to get familiar with VS 2010 and DAC packs. Like it or not, they're both coming. Cheers, Tony.

  Read the article

• SQL SERVER – BACKUPIO, BACKUPBUFFER – Wait Type – Day 14 of 28

  - by pinaldave

  Backup is the most important task for any database admin. Your data is at risk if you are not performing database backup. Honestly, I have seen many DBAs who know how to take backups but do not know how to restore it. (Sigh!) In this blog post we are going to discuss about one of my real experiences with one of my clients – BACKUPIO. When I started to deal with it, I really had no idea how to fix the issue. However, after fixing it at two places, I think I know why this is happening but at the same time, I am not sure the fix is the best solution. The reality is that the fix is not a solution but a workaround (which is not optimal, but get your things done). From Book On-Line: BACKUPIO Occurs when a backup task is waiting for data, or is waiting for a buffer in which to store data. This type is not typical, except when a task is waiting for a tape mount. BACKUPBUFFER Occurs when a backup task is waiting for data, or is waiting for a buffer in which to store data. This type is not typical, except when a task is waiting for a tape mount. BACKUPIO and BACKUPBUFFER Explanation: This wait stats will occur when you are taking the backup on the tape or any other extremely slow backup system. Reducing BACKUPIO and BACKUPBUFFER wait: In my recent consultancy, backup on tape was very slow probably because the tape system was very old. During the time when I explained this wait type reason in the consultancy, the owners immediately decided to replace the tape drive with an alternate system. They had a small SAN enclosure not being used on side, which they decided to re-purpose. After a week, I had received an email from their DBA, saying that the wait stats have reduced drastically. At another location, my client was using a third party tool (please don’t ask me the name of the tool) to take backup. This tool was compressing the backup along with taking backup. I have had a very good experience with this tool almost all the time except this one sparse experience. When I tried to take backup using the native SQL Server compressed backup, there was a very small value on this wait type and the backup was much faster. However, when I attempted with the third party backup tool, this value was very high again and was taking much more time. The third party tool had many other features but the client was not using these features. We end up using the native SQL Server Compressed backup and it worked very well. If I get to see this higher in my future consultancy, I will try to understand this wait type much more in detail and so probably I would able to come to some solid solution. Read all the post in the Wait Types and Queue series. Note: The information presented here is from my experience and there is no way that I claim it to be accurate. I suggest reading Book OnLine for further clarification. All the discussion of Wait Stats in this blog is generic and varies from system to system. It is recommended that you test this on a development server before implementing it to a production server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

  Read the article

• 65536% Autogrowth!

  - by Tara Kizer

  Twice a year, we move our production systems to our disaster recovery site.  Last Saturday night was one of those days.  There are about 50 SQL Server databases to be moved to the DR site, which is done via database mirroring.  It takes only a few seconds to failover, but some databases have a bit more involved work such as setting up replication.  Everything went relatively smooth, but we encountered a weird bug on our most mission critical system.  After everything was successfully failed over to the DR site, it was noticed that mirroring was in a suspended state on one of the databases.  We thought we had run into a SQL Server 2005 bug that we had been encountering and were working with Microsoft on a fix.  Microsoft did fix it in both SQL Server 2005 service pack 3 cumulative update package 13 and service pack 4 cumulative update package 2, however SP3 CU13 and SP4 both recently failed on this system so we were not patched yet with the bug fix.  As the suspended state was causing us issues with replication, we dropped mirroring.  We then noticed we had 10MB of free disk space on the mount point where the principal’s data files are stored.  I knew something went amiss as this system should have at least 150GB free on that mount point.  I immediately checked the main database’s data file and was shocked to see an autgrowth size of 65536%.  The data file autogrew right before mirroring went into the suspended state. 65536%! I didn’t have a lot of time to research if this autgrowth problem was a known SQL Server bug, so I deferred that research to today.  A quick Google search yielded no results but emphasis on “quick”.  I checked our performance system, which was recently restored with a copy of the affected production database, and found the autogrowth setting to be 512MB.  So this autogrowth bug was encountered sometime in the last two weeks.  On February 26th, we had attempted to install SQL 2005 SP4 on production, however it had failed (PSS case open with Microsoft).  I suspected that the SP4 failure was somehow related to this autgrowth bug although that turned out not to be the case. I then tweeted (@TaraKizer) about this problem to see if the SQL Server community (#sqlhelp) had any insights.  It seems several people have either heard of this bug or encountered it.  Aaron Bertrand (blog|twitter) referred me to this Connect item. Our affected database originated on SQL Server 2000 and was upgraded to SQL Server 2005 in 2007.  Back on SQL Server 2000, we were using the default file growth setting which was a percentage.  Sometime after the 2005 upgrade is when we changed it to 512MB.  Our situation seemed to fit the bug Aaron referred to me, so now the question was whether Microsoft had fixed it yet. I received a reply to my tweet from Amit Banerjee (twitter) that it had been fixed in SP3 CU1 (KB958004).  My affected system is SP3 CU8, so I was initially confused why we had encountered the bug.  Because I don’t read things fully, I had missed that there are additional steps you have to follow after applying the bug fix.  Amit set me straight.  Although you can read this information in the KB article, I will also copy it here in case you are as lazy as me and miss the most important section of it (although if you are as lazy as me, you won’t have read this far down my blog post): This hotfix will prevent only future occurrences of this problem. For example, if you restore a database from SQL Server 2000 to a SQL Server 2005 instance that contains this hotfix, this problem will not occur. However, if you already have a database that is affected by this problem, you must follow these steps to resolve this problem manually: Apply this hotfix. Set the file growth settings for the affected files to percentage settings, and then set the settings back to megabyte settings. Take the database offline, and then bring it back online. Verify that the values of the is_percent_growth column are correct in the sys.database_files system table and in the sys.master_files system table.

  Read the article

• Building on someone else's DefaultButton Silverlight work...

  - by KyleBurns

  This week I was handed a "simple" requirement - have a search screen execute its search when the user pressed the Enter key instead of having to move hands from keyboard to mouse and click Search.  That is a reasonable request that has been met for years both in Windows and Web apps.  I did a quick scan for code to pilfer and found Patrick Cauldwell's Blog posting "A 'Default Button' In Silverlight".  This posting was a great start and I'm glad that the basic work had been done for me, but I ran into one issue - when using bound textboxes (I'm a die-hard MVVM enthusiast when it comes to Silverlight development), the search was being executed before the textbox I was in when the Enter key was pressed updated its bindings.  With a little bit of reflection work, I think I have found a good generic solution that builds upon Patrick's to make it more binding-friendly.  Also, I wanted to set the DefaultButton at a higher level than on each TextBox (or other control for that matter), so the use of mine is intended to be set somewhere such as the LayoutRoot or other high level control and will apply to all controls beneath it in the control tree.  I haven't tested this on controls that treat the Enter key special themselves in the mix. The real change from Patrick's solution here is that in the KeyUp event, I grab the source of the KeyUp event (in my case the textbox containing search criteria) and loop through the static fields on the element's type looking for DependencyProperty instances.  When I find a DependencyProperty, I grab the value and query for bindings.  Each time I find a binding, UpdateSource is called to make sure anything bound to any property of the field has the opportunity to update before the action represented by the DefaultButton is executed. Here's the code: public class DefaultButtonService { public static DependencyProperty DefaultButtonProperty = DependencyProperty.RegisterAttached("DefaultButton", typeof (Button), typeof (DefaultButtonService), new PropertyMetadata (null, DefaultButtonChanged)); private static void DefaultButtonChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { var uiElement = d as UIElement; var button = e.NewValue as Button; if (uiElement != null && button != null) { uiElement.KeyUp += (sender, arg) => { if (arg.Key == Key.Enter) { var element = arg.OriginalSource as FrameworkElement; if (element != null) { UpdateBindings(element); } if (button.IsEnabled) { button.Focus(); var peer = new ButtonAutomationPeer(button); var invokeProv = peer.GetPattern(PatternInterface.Invoke) as IInvokeProvider; if (invokeProv != null) invokeProv.Invoke(); arg.Handled = true; } } }; } } public static DefaultButtonService GetDefaultButton(UIElement obj) { return (DefaultButtonService) obj.GetValue(DefaultButtonProperty); } public static void SetDefaultButton(DependencyObject obj, DefaultButtonService button) { obj.SetValue(DefaultButtonProperty, button); } public static void UpdateBindings(FrameworkElement element) { element.GetType().GetFields(BindingFlags.Public | BindingFlags.Static).ForEach(field => { if (field.FieldType.IsAssignableFrom(typeof(DependencyProperty))) { try { var dp = field.GetValue(null) as DependencyProperty; if (dp != null) { var binding = element.GetBindingExpression(dp); if (binding != null) { binding.UpdateSource(); } } } // ReSharper disable EmptyGeneralCatchClause catch (Exception) // ReSharper restore EmptyGeneralCatchClause { // swallow exceptions } } }); } }

  Read the article

• Fixing some Visual Studio RC install issues

  - by terje

  The Visual Studio RC has shown some install issues in some cases, particularly for those who upgrades from VS 11 Beta.  I have listed the fixes known now below, and will update if there are more issues.  Note that a repair will not fix the issue, and a Windows restore and subsequent reinstall may not fix it either.  The system seems to remember too much. That was the case for me, at least.  The fixes below however, cures these issues. 1. The Team Explorer Build node doesn’t work You get an error saying System.TypeLoadException like this: To solve this do as follows: 1. Open a command prompt as administrator 2. Go to your program files directory for VS 2012 and down to  the extension folder like:   C:\Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE\CommonExtensions\Microsoft\TeamFoundation\Team Explorer 3. Run “gacutil –if Microsoft.TeamFoundation.Build.Controls.dll     2. The SQL Editor gives loading error When you start up VS 2012 RC you get a loading error message.  The same happens if you try to go from the menu to  SQL/Transact-SQL Editor/New Query.    To solve this do as follows: 1. Open Control Panel/Programs and Features 2. Locate the “Microsoft SQL Server 2012 Data-Tier App Framework     (Note , you might find up to 4 such instances) The ones with version numbers ending in 55 is from the SQL 2012 RC, the ones ending in 60 is from the SQL 2012 RTM.  There are two of each, one for x32 and one for x64.  Which is which no one knows. 3. Right click each of them, and select Repair. (It would be nice if someone with this issue tries only the latest RTM ones, and see if that clears the error, and comment back to this post. I am out of non-functioning VS’s )   3.  Errors referring to some extension You get errors referring to some extension that can’t be loaded, or can’t be found.  Check the activity log (see below), and verify there.  If you see yellow collision warnings there, the fix here should solve those too. To solve these:    1. Open a Visual Studio 2012 command prompt 2.  Run:   devenv /resetsettings     How to check for errors using the log Do as follows to get to the activity log for Visual studio 2012 RC 1. Open a Visual Studio 2012 command prompt 2. Run:   devenv /log This starts up Visual Studio.  3. Go to %appdata%/Microsoft\VisualStudio\11.0 4. Double click the file named ActivityLog.xml.  It will start up in your browser, and be formatted using the xslt in the same directory. 5.  Look for items marked in red.  Example for Issue 1 :

  Read the article

• Drawing texture does not work anymore with a small amount of triangles

  - by Paul

  When i draw lines, the vertices are well connected. But when i draw the texture inside the triangles, it only works with i<4 in the for loop, otherwise with i<5 for example, there is a EXC_BAD_ACCESS message, at @synthesize textureImage = _textureImage. I don't understand why. (The generatePolygons method seems to work fine as i tried to draw lines with many vertices as in the second image below. And textureImage remains the same for i<4 or i<5 : it's a 512px square image). Here are the images : What i want to achieve is to put the red points and connect them to the y-axis (the green points) and color the area (the green triangles) : If i only draw lines, it works fine : Then with a texture color, it works for i<4 in the loop (the red points in my first image, plus the fifth one to connect the last y) : But then, if i set i<5, the debug tool says EXC_BAD_ACCESS at the synthesize of _textureImage. Here is my code : I set a texture color in HelloWordLayer.mm with : CCSprite *textureImage = [self spriteWithColor:color3 textureSize:512]; _terrain.textureImage = textureImage; Then in the class Terrain, i create the vertices and put the texture in the draw method : @implementation Terrain @synthesize textureImage = _textureImage; //EXC_BAD_ACCESS for i<5 - (void)generatePath2{ CGSize winSize = [CCDirector sharedDirector].winSize; float x = 40; float y = 0; for(int i = 0; i < kMaxKeyPoints+1; ++i) { _hillKeyPoints[i] = CGPointMake(x, y); x = 150 + (random() % (int) 30); y += 30; } } -(void)generatePolygons{ _nPolyVertices = 0; float x1 = 0; float y1 = 0; int keyPoints = 0; for (int i=0; i<4; i++){ /* HERE : 4 = OK / 5 = crash */ //V0: at (0,0) _polyVertices[_nPolyVertices] = CGPointMake(x1, y1); _polyTexCoords[_nPolyVertices++] = CGPointMake(x1, y1); //V1: to the first "point" _polyVertices[_nPolyVertices] = CGPointMake(_hillKeyPoints[keyPoints].x, _hillKeyPoints[keyPoints].y); _polyTexCoords[_nPolyVertices++] = CGPointMake(_hillKeyPoints[keyPoints].x, _hillKeyPoints[keyPoints].y); keyPoints++; //from point at index 0 to 1 //V2, same y as point n°2: _polyVertices[_nPolyVertices] = CGPointMake(0, _hillKeyPoints[keyPoints].y); _polyTexCoords[_nPolyVertices++] = CGPointMake(0, _hillKeyPoints[keyPoints].y); //V1 again _polyVertices[_nPolyVertices] = _polyVertices[_nPolyVertices-2]; _polyTexCoords[_nPolyVertices++] = _polyVertices[_nPolyVertices-2]; //V2 again _polyVertices[_nPolyVertices] = _polyVertices[_nPolyVertices-2]; _polyTexCoords[_nPolyVertices++] = _polyVertices[_nPolyVertices-2]; //V3 = same x,y as point at index 1 _polyVertices[_nPolyVertices] = CGPointMake(_hillKeyPoints[keyPoints].x, _hillKeyPoints[keyPoints].y); _polyTexCoords[_nPolyVertices] = CGPointMake(_hillKeyPoints[keyPoints].x, _hillKeyPoints[keyPoints].y); y1 = _polyVertices[_nPolyVertices].y; _nPolyVertices++; } } - (id)init { if ((self = [super init])) { [self generatePath2]; [self generatePolygons]; } return self; } - (void) draw { //glDisable(GL_TEXTURE_2D); glDisableClientState(GL_COLOR_ARRAY); glDisableClientState(GL_TEXTURE_COORD_ARRAY); glBindTexture(GL_TEXTURE_2D, _textureImage.texture.name); glColor4f(1, 1, 1, 1); glVertexPointer(2, GL_FLOAT, 0, _polyVertices); glTexCoordPointer(2, GL_FLOAT, 0, _polyTexCoords); glDrawArrays(GL_TRIANGLE_STRIP, 0, (GLsizei)_nPolyVertices); glColor4f(1, 1, 1, 1); for(int i = 1; i < 40; ++i) { ccDrawLine(_polyVertices[i-1], _polyVertices[i]); } // restore default GL states glEnable(GL_TEXTURE_2D); glEnableClientState(GL_COLOR_ARRAY); glEnableClientState(GL_TEXTURE_COORD_ARRAY); } Do you see anything wrong in this code? Thanks for your help

  Read the article

• Need help partitioning when reinstalling Ubuntu 14.04

  - by Chris M.

  I upgraded to 14.04 about a month ago on my HP Mini netbook (about 16 GB hard disk). A few days ago the system crashed (I don't know why but I was using internet at the time). When I restarted the computer, Ubuntu would not load. Instead, I got a message from the BIOS saying Reboot and Select proper Boot device or Insert Boot Media in selected Boot device and press a key I took this to mean that I needed to reinstall 14.04. When I try to reinstall Ubuntu from the USB stick, I choose "Erase disk and install Ubuntu" but then I get a message: Some of the partitions you created are too small. Please make the following partitions at least this large: / 3.3 GB If you do not go back to the partitioner and increase the size of these partitions, the installation may fail. At first I hit Continue to see if it would install anyway, and it gave the message: The attempt to mount a file system with type ext4 in SCSI1 (0,0,0), partition # 1 (sda) at / failed. You may resume partitioning from the partitioning menu. The second time I hit Go Back, and it took me to the following partitioning table: Device Type Mount Point Format Size Used System /dev/sda /dev/sda1 ext4 (checked) 3228 MB Unknown /dev/sda5 swap (not checked) 1063 MB Unknown + - Change New Partition Table... Revert Device for boot loader installation: /dev/sda ATA JM Loader 001 (4.3 GB) At this point I'm not sure what to do. I've never partitioned my hard drive before and I don't want to screw things up. (I'm not particularly tech savvy.) Can you instruct me what I should do. (P.S. I'm afraid the table might not appear as I typed it in.) Results from fdisk: ubuntu@ubuntu:~$ sudo fdisk -l Disk /dev/sda: 4294 MB, 4294967296 bytes 255 heads, 63 sectors/track, 522 cylinders, total 8388608 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/sda doesn't contain a valid partition table Disk /dev/sdb: 7860 MB, 7860125696 bytes 155 heads, 31 sectors/track, 3194 cylinders, total 15351808 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0009a565 Device Boot Start End Blocks Id System /dev/sdb1 * 2768 15351807 7674520 b W95 FAT32 ubuntu@ubuntu:~$ Here is what it displays when I open the Disks utility (I tried the screenshot terminal command you suggested but it didn't seem to do anything): 4.3 GB Hard Disk /dev/sda Model: JM Loader 001 (01000001) Size: 4.3 GB (4,294,967,296 bytes) Serial Number: 01234123412341234 Assessment: SMART is not supported Volumes Size: 4.3 GB (4,294,967,296 bytes) Device: /dev/sda Contents: Unknown (There is a button in the utility that when you click it gives the following options: Format... Create Disk Image... Restore Disk Image... Benchmark but SMART Data & Self-Tests... is dimmed out) When I hit F9 Change Boot Device Order, it shows the hard drive as: SATA:PM-JM Loader 001 When I hit F10 to get me into the BIOS Setup Utility, under Diagnostic it shows: Primary Hard Disk Self Test Not Support NetworkManager Tool State: disconnected Device: eth0 Type: Wired Driver: atl1c State: unavailable Default: no HW Address: 00:26:55:B0:7F:0C Capabilities: Carrier Detect: yes Wired Properties Carrier: off When I run command lshw -C network, I get: WARNING: you should run this program as super-user. *-network description: Network controller product: BCM4312 802.11b/g LP-PHY vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:01:00.0 version: 01 width: 64 bits clock: 33MHz capabilities: bus_master cap_list configuration: driver=b43-pci-bridge latency=0 resources: irq:16 memory:feafc000-feafffff *-network description: Ethernet interface product: AR8132 Fast Ethernet vendor: Qualcomm Atheros physical id: 0 bus info: pci@0000:02:00.0 logical name: eth0 version: c0 serial: 00:26:55:b0:7f:0c capacity: 100Mbit/s width: 64 bits clock: 33MHz capabilities: bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=atl1c driverversion=1.0.1.1-NAPI latency=0 link=no multicast=yes port=twisted pair resources: irq:43 memory:febc0000-febfffff ioport:ec80(size=128) WARNING: output may be incomplete or inaccurate, you should run this program as super-user.

  Read the article

• Upgraded to 12.04 now wifi doesn't work

  - by Benito Kestelman

  My laptop's wifi stopped working when I upgraded to Ubuntu 12.04 (wired works). I just reinstalled 12.04 over my old 12.04 on which wifi didn't work either in an attempt to restore any settings I may have accidentally changed, but it still doesn't work. I also used a wired connection to install updates in case this bug has been fixed, but it has not. Here is the result of sudo lshw -class network: *-network description: Wireless interface product: Centrino Wireless-N + WiMAX 6150 vendor: Intel Corporation physical id: 0 bus info: pci@0000:02:00.0 logical name: wlan0 version: 67 serial: 40:25:c2:5f:5b:f4 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=iwlwifi driverversion=3.2.0-29-generic-pae firmware=41.28.5.1 build 33926 latency=0 link=no multicast=yes wireless=IEEE 802.11bgn resources: irq:51 memory:de800000-de801fff *-network description: Ethernet interface product: AR8151 v2.0 Gigabit Ethernet vendor: Atheros Communications Inc. physical id: 0 bus info: pci@0000:04:00.0 logical name: eth0 version: c0 serial: 14:da:e9:c0:da:78 capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress vpd bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=atl1c driverversion=1.0.1.0-NAPI firmware=N/A latency=0 link=no multicast=yes port=twisted pair resources: irq:54 memory:dd400000-dd43ffff ioport:a000(size=128) Here is rfkill list all: 0: phy0: Wireless LAN Soft blocked: no Hard blocked: no 1: asus-wlan: Wireless LAN Soft blocked: no Hard blocked: no 2: asus-wimax: WiMAX Soft blocked: no Hard blocked: no lsusb: Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 003: ID 8087:07d6 Intel Corp. Bus 001 Device 004: ID 13d3:5710 IMC Networks Bus 002 Device 003: ID 045e:0745 Microsoft Corp. Nano Transceiver v1.0 for Bluetooth Bus 003 Device 003: ID 0781:5530 SanDisk Corp. Cruzer lspci: 00:00.0 Host bridge: Intel Corporation 2nd Generation Core Processor Family DRAM Controller (rev 09) 00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09) 00:16.0 Communication controller: Intel Corporation 6 Series/C200 Series Chipset Family MEI Controller #1 (rev 04) 00:1a.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2 (rev 05) 00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller (rev 05) 00:1c.0 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 1 (rev b5) 00:1c.1 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 2 (rev b5) 00:1c.3 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 4 (rev b5) 00:1c.5 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 6 (rev b5) 00:1d.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1 (rev 05) 00:1f.0 ISA bridge: Intel Corporation HM65 Express Chipset Family LPC Controller (rev 05) 00:1f.2 SATA controller: Intel Corporation 6 Series/C200 Series Chipset Family 6 port SATA AHCI Controller (rev 05) 00:1f.3 SMBus: Intel Corporation 6 Series/C200 Series Chipset Family SMBus Controller (rev 05) 02:00.0 Network controller: Intel Corporation Centrino Wireless-N + WiMAX 6150 (rev 67) 03:00.0 USB controller: ASMedia Technology Inc. ASM1042 SuperSpeed USB Host Controller 04:00.0 Ethernet controller: Atheros Communications Inc. AR8151 v2.0 Gigabit Ethernet (rev c0)

  Read the article

• Move over DFS and Robocopy, here is SyncToy!

  - by andywe

  Ever since Windows 2000, I have always had the need to replicate data to multiple endpoints with the same content. Until DFS was introduced, the method of thinking was to either manually copy the data location by location, or to batch script it with xcopy and schedule a task. Even though this worked (and still does today), it was cumbersome, and intensive on the network, especially when dealing with larger amounts of data. Then along came robocopy, as an internal tool written by an enterprising programmer at Microsoft. We used it quite a bit, especially when we could not use DFS in the early days. It was received so well, it made it into the public realm. At least now we could have the ability to determine what files had changed and only replicate those. Well, over time there has been evolution of this ideal. DFS is obviously the Windows enterprise class service to do this, along with BrancheCache..however you don’t always need or want the power of DFS, especially when it comes to small datacenter installations, or remote offices. I have specific data sets that are on closed or restricted networks, that either have a security need for this, or are in remote countries where bandwidth is a premium. FOr this, I use the latest evolution for one off replication names Synctoy. Synctoy is from Microsoft, seemingly released in 2009, that wraps a nice GUI around setting up a paired set of folders (remember the mobile briefcase from Windows 98?), and allowing you the choice of synchronization methods. 1 way, or 2 way. Simply create a paired set of folders on the source and destination, choose your options for content, exclude any file types you don’t want to replicate, and click run. Scheduling is even easier. MS has included a wrapper for doing just this so all you enter in your task schedule in the SynToyCMD.exe, a –R as an argument, and the time schedule. No more complicated command lines or scripts.   I find this especially useful when I use MS backup to back up a system volume, but only want subsets of backup information of a data share and ONLY when that dataset has changed. Not relying on full backups and incremental. An example of this is my application installation master share. I back this up with SyncToy because I do not need multiple backup copies..one copy elsewhere suffices to back it up. At home, very useful for your pictures, videos, music, ect..the backup is online and ready to access, not waiting for you to restore a backup file, and no need to institute a domain simply to have DFS.'   Do note there is a risk..if you accidently delete a file and do not catch this before the next sync, then depending on your SyncToy settings, you can indeed lose that file as the destination updates..so due diligence applies. I make it a rule to sync manly one way…I use my master share for making changes, and allow the schedule to follow suit. Any real important file I lock down as read only through file permissions so it cannot be deleted unless I intervene.   Check out the tool and have some fun! http://www.microsoft.com/en-us/download/details.aspx?DisplayLang=en&id=15155

  Read the article

• The long road to bug-free software

  - by Tony Davis

  The past decade has seen a burgeoning interest in functional programming languages such as Haskell or, in the Microsoft world, F#. Though still on the periphery of mainstream programming, functional programming concepts are gradually seeping into the imperative C# language (for example, Lambda expressions have their root in functional programming). One of the more interesting concepts from functional programming languages is the use of formal methods, the lofty ideal behind which is bug-free software. The idea is that we write a specification that describes exactly how our function (say) should behave. We then prove that our function conforms to it, and in doing so have proved beyond any doubt that it is free from bugs. All programmers already use one form of specification, specifically their programming language's type system. If a value has a specific type then, in a type-safe language, the compiler guarantees that value cannot be an instance of a different type. Many extensions to existing type systems, such as generics in Java and .NET, extend the range of programs that can be type-checked. Unfortunately, type systems can only prevent some bugs. To take a classic problem of retrieving an index value from an array, since the type system doesn't specify the length of the array, the compiler has no way of knowing that a request for the "value of index 4" from an array of only two elements is "unsafe". We restore safety via exception handling, but the ideal type system will prevent us from doing anything that is unsafe in the first place and this is where we start to borrow ideas from a language such as Haskell, with its concept of "dependent types". If the type of an array includes its length, we can ensure that any index accesses into the array are valid. The problem is that we now need to carry around the length of arrays and the values of indices throughout our code so that it can be type-checked. In general, writing the specification to prove a positive property, even for a problem very amenable to specification, such as a simple sorting algorithm, turns out to be very hard and the specification will be different for every program. Extend this to writing a specification for, say, Microsoft Word and we can see that the specification would end up being no simpler, and therefore no less buggy, than the implementation. Fortunately, it is easier to write a specification that proves that a program doesn't have certain, specific and undesirable properties, such as infinite loops or accesses to the wrong bit of memory. If we can write the specifications to prove that a program is immune to such problems, we could reuse them in many places. The problem is the lack of specification "provers" that can do this without a lot of manual intervention (i.e. hints from the programmer). All this might feel a very long way off, but computing power and our understanding of the theory of "provers" advances quickly, and Microsoft is doing some of it already. Via their Terminator research project they have started to prove that their device drivers will always terminate, and in so doing have suddenly eliminated a vast range of possible bugs. This is a huge step forward from saying, "we've tested it lots and it seems fine". What do you think? What might be good targets for specification and verification? SQL could be one: the cost of a bug in SQL Server is quite high given how many important systems rely on it, so there's a good incentive to eliminate bugs, even at high initial cost. [Many thanks to Mike Williamson for guidance and useful conversations during the writing of this piece] Cheers, Tony.

  Read the article

• When things go awry

  - by Phil Factor

  The moment the Entrepreneur opened his mouth on prime-time national TV, spelled out the URL and waxed big on how exciting ‘his’ new website was, I knew I was in for a busy night. I’d designed and built it. All at once, half a million people tried to log into the website. Although all my stress-testing paid off, I have to admit that the network locked up tight long before there was any danger of a database or website problem. Soon afterwards, the Entrepreneur and the Big Boss were there in the autopsy meeting. We picked through all our systems in detail to see how they’d borne the unexpected strain. Mercifully, in view of the sour mood of the Big Boss, it turned out that the only thing we could have done better was buy a bigger pipe to and from the internet. We’d specified that ‘big pipe’ when designing the system. The Big Boss had then railed at the cost and so we’d subsequently compromised. I felt that my design decisions were vindicated. The Big Boss brooded for a while. Then he made the significant comment: “What really ****** me off is the fact that, for ten minutes, we couldn’t take people’s money.” At that point I stopped feeling smug. Had the internet connection been better, the system would have reached its limit and failed rather precipitously, and that wasn’t what he wanted. Then it occurred to me that what had gummed up the connection was all those images on the site, that had made it so impressive for the visitors. If there had been a way to automatically pare down the site to the bare essentials under stress… Hmm. I began to consider disaster-recovery in the broadest sense – maintaining a service in spite of unusual or unexpected events. What he said makes a lot of sense: sacrifice whatever isn’t essential to keep the core service running when we approach the capacity limits. Maybe in IT we should borrow (or revive) the business concept of the ‘Skeleton service’, maintaining only the priority parts under stress, using a process that is well-prepared and carefully rehearsed. How might this work? Whatever the event we have to prepare for, it is all about understanding the priorities; knowing what one can dispense with when the going gets tough. In the event of database disaster, it’s much faster to deploy a skeletal system with only the essential data than to restore the entire system, though there would have to be a reconciliation process to update the revived database retrospectively, once the emergency was over. It isn’t just the database that could be designed for resilience. One could prepare for unusually high traffic in a website by designing a system that degraded gradually to a ‘skeletal’ site, one that maintained the commercial essentials without fat images, JavaScript libraries and razzmatazz. This is all what the Big Boss scathingly called ‘a mere technicality’. It seems to me that what is needed first is a culture of application and database design which acknowledges that we live in a very imperfect world, and react accordingly when things go awry.

  Read the article

• SSMS Tools Pack 2.7 is released. New website, improved licensing and features.

  - by Mladen Prajdic

  New website Nice, isn't it? Cleaner, simpler, better looking and more modern. If you have any suggestions for further improvements I'd be glad to hear them. Simpler licensing With SSMS tools Pack 2.7 the licensing is finally where it should be. It is now based on the activate/deactivate model. This way you can move a license from machine to machine with simple deactivation on one and reactivation on another machine. Much better, no? Because of very good feedback I have added an option for 6 machines and lowered the 4 machines option to 3 machines. This should make it much simpler for you to choose the right option for yourself. Improved features Version 2.5.3 was already extremely stable and 2.7 continues with that tradition. Because of that I could fully focus on features and why 3.0 will rock even more that 2.7! ;) In version 2.7 I have addressed quite a few improvements you were requesting for a while now. SQL History This is probably the biggest time saver out there, therefore it's only fair it gets a few important updates. If you have an existing .sql file opened, the Window Content History now saves your code to that existing file and also makes a backup in the SQL History log default location. Search is still done through the SQL History log but the Tab Sessions Restore opens your existing .sql file. This way you don't have to remember to save your existing files by yourself anymore. A bug when you couldn't search properly if you copied the log files to a new location was fixed. Unfortunately this removed the option to filter a search with the time component. The smallest search interval is now one day. The SSMS Tools Pack now remembers the visibility of the Current Window History window when you exit SSMS. SQL Snippets You can now set the position of the cursor in your snippets by placing {C} somewhere in your snippet. It's a small improvement but can be a huge time saver since you don't have to move through the snippet to the desired location anymore. Run script on multiple databases Database choices can now be saved with a name and then loaded again next time. You can also choose to run the script in a new window for each chosen database. Search through grid results You can now go previous/next search result with the Prev/Next control inside the search window. This is extremely useful if you have a large resultset. IT saves you the scrolling. CRUD generator Four new variables have been added: |CurrentDate| writes current date in format yyyy-MM-dd to your script |CurrentTime| writes current time in 24h format HH:mm:ss to your script |CurrentWinUser| writes current Windows logged on user to your script |CurrentSqlUser| writes current SQL logged on login to your script This was actually quite a requested feature so if you have any other ideas for extra variables, do let me know. That's about it. I hope you're going to enjoy this version as much as the previous ones. Have fun!

  Read the article

• MySQL Enterprise Backup 3.8.2 has been released!

  - by Hema Sridharan

  MySQL Enterprise Backup v3.8.2, a maintenance release of online MySQL backup tool, is now available for download from My Oracle Support  (MOS) website as our latest GA release.  It will also be available via the Oracle Software Delivery Cloud in approximately 1-2 weeks. A brief summary of the changes in MySQL Enterprise Backup version 3.8.2 is given below.   A. Functionality Added or Changed:  MySQL Enterprise Backup has a new --on-disk-full command line option. mysqlbackup could hang when the disk became full, rather than detecting the low space condition. mysqlbackup now monitors disk space when running backup commands, and users can now specify the action to take at a disk-full condition with the --on-disk-full option. For more details, refer this page MySQL Enterprise Backup has a new progress report feature, which periodically outputs short progress indicators on its  operations to user-selected destinations (for example, stdout, stderr, a file, or other choices). For more details on progress report options, refer here   B. Bugs Fixed: When --innodb-file-per-table=ON, if a table was renamed and backup-to-image was in progress, apply-log would fail when being run on the backup. (Bug #16903973)   MySQL Server failed to start after a backup was restored if  there had been online DDL transactions on partitioned tables during the time of backup. (Bug #16924499)   apply-log failed if ALTER TABLE ... REORGANIZE PARTITION was applied to partitioned InnoDB tables during backup. (Bug #16721824, Bug #16903951)  apply-incremental-backup might fail with an assertion error if  the InnoDB tables being backed up were created in Barracuda format and with their KEY_BLOCK_SIZE  values  different from the innodb_page_size . This fix ensures that different KEY_BLOCK_SIZE  values are handled properly during incremental backup and apply-incremental-backup operations.  If a table was renamed following a full backup, a subsequent incremental backup could copy the .frm file with the new name, but not the associated .ibd file with the new name. After a  restore, the InnoDB data dictionary could be in an  inconsistent state. This issue primarily occurred if the table  was not changed between the full backup and the subsequent  incremental backup. Bug #16262690)  After a full backup, if a table was renamed and modified,  apply-incremental-backup would crash when run on the backup directory. (Bug #16262609) The value of the binary log position in backup_variables.txt  could be different from the output displayed during the   backup-and-apply-log operation. (This issue did not occur if  the backup and apply-log steps were done separately.) (Bug  #16195529) When using the --only-innodb-with-frm option, MySQL Enterprise Backup tried to create temporary files at unintended locations in the file system, which might cause a failure when, for example, the user had no write privilege for those locations.   This fix makes sure the paths for the temporary files are  correct. (Bug #14787324)  A backup process might hang when it ran into an LSN mismatch between a data file  and the redo log. This fix makes sure the process does not hang and it displays an error message showing the  name of the problematic data file (Bug #14791645) Please post your questions / comments about Backup in forums. Thanks, MEB Team

  Read the article

• Using 3rd Party JavaScript Plugins Hardwired With &lsquo;document.write&rsquo;

  - by ToStringTheory

  Introduction Have you ever had the need to implement a 3rd party JavaScript plugin, but your needs didn’t fit the model and usage defined by the API or documentation of the plugin?  Recently I ran into this issue when I was trying to implement a web snapshot plugin into our site.  To use their plugin, you had to include a script tag to the plugin on their server with an API key.  The second part of the usage was to include a <script> tag around a function call wherever you wanted a snapshot to appear. The Problem When trying to use the service, the images did not display.  I checked a couple of things and didn’t find anything wrong at first..  It wasn’t until I looked at the function that was called by the inline script did I find the issue – a call to the webservice, followed by a call to ‘document.write’ in its callback.  The solution in which I was trying to implement the plugin happened to be in response to an AJAX call after the document had completely loaded.  After the page has loaded, document.write does nothing. My first thought for a solution was to just cache the script from the service, and edit it do something like a return function or callback that I could use to edit the document from.  However, I quickly discovered that there is no way to cache the script from the service, as it had a hash in the function where it would call the server.  The hash was updated every few seconds/minutes, expiring old hashes.  This meant that I wouldn’t be able to edit the script and upload a new version to my server, as the script would not work after a few minutes from originally getting the script from the service. Solution The solution eluded me until I realized that this was JavaScript I was dealing with.  A language designed so that you could do just about anything to any library, function, or object…  At this point, the solution was simple – take control of the document.write function.  Using a buffer variable, and a simple function call, it is eerily simple to perform: //what would have been output to the document var buffer = ""; //store a reference to the real document.write var dw = document.write; //redefine document.write to store to our buffer document.write = function (str) {buffer += str;} //execute the function containing calls to document.write eval('{function encapsulated in <script></script> tags}'); //restore the original document.write function (just in case) document.write = dw; That’s it.  Instead of using the script tags where I wanted to include a snapshot, I called a function passing in the URL to the page I wanted a snapshot of.  After that last line of code, what would have been output to the document (or not in the case of the ajax call) was instead stored in buffer. Conclusion While the solution itself is simple, coming from a background much more footed in the .Net platform, I believe that this is a prime example of always keeping the language that you are working in in mind.  While this may seem obvious at first, as I KNEW I was in JavaScript, I never thought of taking control of the document.write function because I am more accustomed to the .Net world.  I can’t simply replace the functionality of Console.WriteLine.

  Read the article

• The long road to bug-free software

  - by Tony Davis

  The past decade has seen a burgeoning interest in functional programming languages such as Haskell or, in the Microsoft world, F#. Though still on the periphery of mainstream programming, functional programming concepts are gradually seeping into the imperative C# language (for example, Lambda expressions have their root in functional programming). One of the more interesting concepts from functional programming languages is the use of formal methods, the lofty ideal behind which is bug-free software. The idea is that we write a specification that describes exactly how our function (say) should behave. We then prove that our function conforms to it, and in doing so have proved beyond any doubt that it is free from bugs. All programmers already use one form of specification, specifically their programming language's type system. If a value has a specific type then, in a type-safe language, the compiler guarantees that value cannot be an instance of a different type. Many extensions to existing type systems, such as generics in Java and .NET, extend the range of programs that can be type-checked. Unfortunately, type systems can only prevent some bugs. To take a classic problem of retrieving an index value from an array, since the type system doesn't specify the length of the array, the compiler has no way of knowing that a request for the "value of index 4" from an array of only two elements is "unsafe". We restore safety via exception handling, but the ideal type system will prevent us from doing anything that is unsafe in the first place and this is where we start to borrow ideas from a language such as Haskell, with its concept of "dependent types". If the type of an array includes its length, we can ensure that any index accesses into the array are valid. The problem is that we now need to carry around the length of arrays and the values of indices throughout our code so that it can be type-checked. In general, writing the specification to prove a positive property, even for a problem very amenable to specification, such as a simple sorting algorithm, turns out to be very hard and the specification will be different for every program. Extend this to writing a specification for, say, Microsoft Word and we can see that the specification would end up being no simpler, and therefore no less buggy, than the implementation. Fortunately, it is easier to write a specification that proves that a program doesn't have certain, specific and undesirable properties, such as infinite loops or accesses to the wrong bit of memory. If we can write the specifications to prove that a program is immune to such problems, we could reuse them in many places. The problem is the lack of specification "provers" that can do this without a lot of manual intervention (i.e. hints from the programmer). All this might feel a very long way off, but computing power and our understanding of the theory of "provers" advances quickly, and Microsoft is doing some of it already. Via their Terminator research project they have started to prove that their device drivers will always terminate, and in so doing have suddenly eliminated a vast range of possible bugs. This is a huge step forward from saying, "we've tested it lots and it seems fine". What do you think? What might be good targets for specification and verification? SQL could be one: the cost of a bug in SQL Server is quite high given how many important systems rely on it, so there's a good incentive to eliminate bugs, even at high initial cost. [Many thanks to Mike Williamson for guidance and useful conversations during the writing of this piece] Cheers, Tony.

  Read the article

< Previous Page | 99 100 101 102 103 104 105 106 107 108 109 110  | Next Page >