Software development & .NET RSS 2.0
 Friday, May 08, 2009
Are you storing passwords in any of your applications? If you are, reconsider. Passwords are very sensitive, because people have so many accounts that they are forced to reuse passwords. Read about what (eventually) will happen: http://www.codinghorror.com/blog/archives/001263.html
Friday, May 08, 2009 5:50:30 PM (W. Europe Daylight Time, UTC+02:00)  #    Comments [0] -
Architecture | Coding
 Sunday, November 16, 2008
Sunday, November 16, 2008 7:44:32 PM (W. Europe Standard Time, UTC+01:00)  #    Comments [0] -
Fun
 Tuesday, October 28, 2008

Keynote: everyone will probably have heard about Azure by now. Although this something that's a big deal for Microsoft from a business perspective, it seemed to lack the 'wow'-factor for developers. It will be interesting to see how the pricing will be. That'll be the biggest hurdle to get mainstream-adoption.

BB11 Identity Roadmap for Software + Services: open up the Active Directory-identities to the web using Geneva. AD-identities are translated to claims which can be used by anyone because it's all standards based.

BB09 Microsoft Office Communications Server and Exchange: Platform Futures: I actually did the HOL before this session. Using the managed provider there's very little left to do to build solutions like Automated Call Distribution.

PC21 ASP.NET MVC: A New Framework for Building Web Applications: control the html and separate concerns using MVC. Stackoverflow is using ASP.NET MVC.

TL17 WF 4.0: A First Look: the next version of WF boasts a 10-100x improvement in performance. Seems to be much improved in usability for the developer.

"Show off" is about to start ...

Tuesday, October 28, 2008 4:28:06 AM (W. Europe Standard Time, UTC+01:00)  #    Comments [0] -
PDC 2008
 Monday, October 27, 2008

The preconference session on WCF by Juwal Lowy was very interesting. Most WCF-talks focus on the mechanics: how to edit the config-file, what to do to use a specific protocol. Juwal instead demonstrated the productivity gains WCF brings to the platform.

Interesting quotes / take aways:

   "The first law of Xml: if you see xml, you're doing something wrong"

   Nobody cares about you doing plumbing ... so don't do plumbing.

Monday, October 27, 2008 6:23:34 AM (W. Europe Standard Time, UTC+01:00)  #    Comments [0] -
PDC 2008
 Saturday, October 25, 2008

I just arrived in Los Angeles. The view from the hotel is a lot better than the previous visits to LA. I've registered for the pre-conference on WCF on Sunday, so I have tomorrow to adjust to the timezone and weather.

Saturday, October 25, 2008 2:48:44 AM (W. Europe Daylight Time, UTC+02:00)  #    Comments [1] -
PDC 2008
 Saturday, February 23, 2008
 Saturday, January 26, 2008
Saturday, January 26, 2008 9:39:55 PM (W. Europe Standard Time, UTC+01:00)  #    Comments [0] -
Fun
 Thursday, July 19, 2007

Nice sample of WPF being applied in an application at http://www.vertigo.com/familyshow.aspx

Don't have the 3.0 framework installed? Get it here

Thursday, July 19, 2007 9:40:28 AM (W. Europe Daylight Time, UTC+02:00)  #    Comments [0] -

 Thursday, July 12, 2007

I just finished the upgrade to das Blog 1.9.7174.0. This version has more support for reducing comment-spam. (See http://www.dasblog.info/ for other changes)
Browsing thru the old posts revealed a large number of 'contributions' from China and the Middle East. For some reason deleting comments from a post that has more than 4 comments takes quite some time. The amount of time increases exponentially with the number of comments. Not sure what causes this.
Luckily v1.9 allows me to prevent comments on posts older than 60 days, so cleaning old posts shouldn't be necessary after this.

One of the 'benefits' of removing comment spam is that it did demonstrate that Vista displays all of those non-western character sets. So we're one step closer in actually understanding what they are trying to sell.

Thursday, July 12, 2007 12:38:02 AM (W. Europe Daylight Time, UTC+02:00)  #    Comments [0] -

 Sunday, January 14, 2007

In his last two posts Anko describes the Peer-to-Peer-replication in SQL Server 2005. It is a valueable tool in improving both the availability and scalability of the database tier. Because the other tiers of the application can be easily 'scaled out' using load balancing this directly affects the scalability and availability of the entire application.

What is scalability? Wikipedia defines it as "Scalability is a desirable property of a system, a network or a process, which indicates its ability to either handle growing amounts of work in a graceful manner, or to be readily enlarged". If your application supports 100 concurrent users, how difficult would it be to support 1000 users? A 'graceful manner' would be to add some extra hardware to the server. It would not be graceful if you had to re-build the entire application.

With the continuing growth of the power of hardware, it becomes increasingly rare that an application would require more than a single database-server to deal with the load. Adding more hardware is called 'Scale up': a more powerful server enables more transactions. Although in most cases a normal server would be sufficient, you could spend a bit more: for a mere 6 million dollars you get over a million tpmC. If the business case requires these numbers of transactions, the cost of the server will probably become less important.

The alternative is 'Scaling out': adding more servers to share the load. Peer-to-Peer-replication enables this kind of scenario. The requirement for consistency between the different nodes makes the scaling out of the database much more difficult than scaling out the web/application-server.

Suppose we have two nodes, A & B, with peer-to-peer replication enabled. In an ideal situation it shouldn't matter which node processes an incoming request. For reading relatively static data this works pretty well. The real challenges come with modifying data. If an insert is performed against node A, you can't succesfully perform an update to that record on node B before the insert from node A is replicated.

The are two ways of solving this problem:

  • Perform modifications on all nodes before completing the transaction
  • Divide the database into logical pieces. Modifications to customers with a name starting with A-M are performed on node A; modifications for names from N to Z are performed on node B.

The last solution is what the article on MSDN suggests. Another solution mentioned in the article is to have all modifications performed on one of the nodes. Read-only tasks could be performed against the other node. This comes pretty close to physically clustering the database, but would still require the application to be aware of the configuration of the database. The application should be able to cope with the situation where an record that's inserted in one node, is not being returned from the 'read-only'-node.

The use of Peer-to-Peer-replication is something that should be decided when developing the architecture of the entire solution. At that time it can be weighed against other options like dividing the application into different subsystems with their own databases and caching data on the web/application-server.

So there are multiple options to scale SQL Server to handle a large number of transactions. Spending enough time on architecture and adding more hardware should cover most requirements. Combined with scaling out it's hard to imagine a load that it would not be able to handle.

Next post we'll look at availabilty.

Sunday, January 14, 2007 5:16:39 PM (W. Europe Standard Time, UTC+01:00)  #    Comments [0] -
Architecture | SQL Server
 Saturday, December 16, 2006

The long awaited sp1 for Visual Studio 2005 is available for download at http://www.microsoft.com/downloads/details.aspx?familyid=BB4A75AB-E2D4-4C96-B39D-37BAF6B5B1DC&displaylang=en

Saturday, December 16, 2006 8:47:51 PM (W. Europe Standard Time, UTC+01:00)  #    Comments [0] -
Tools
 Wednesday, December 13, 2006

The dates for the next PDC are from September 30 thru October 5. Seems that it will be held in LA yet again.

Wednesday, December 13, 2006 10:57:10 AM (W. Europe Standard Time, UTC+01:00)  #    Comments [0] -

 Friday, November 17, 2006

Vista is now available on MSDN!

Friday, November 17, 2006 11:29:04 AM (W. Europe Standard Time, UTC+01:00)  #    Comments [1] -
Longhorn
 Tuesday, November 07, 2006

Office 2007 has been released to manufacturing. Shouldn't be to long before it becomes available on MSDN.

Especially for developers there are a lot of new features. And don't think it's just Word or Excel: there are also new releases of server products like Sharepoint Server and VSTO

http://blogs.msdn.com/erikaehrli/archive/2006/11/06/office2007_5F00_VSTO2005SE_5F00_RTM.aspx

Tuesday, November 07, 2006 11:58:33 AM (W. Europe Standard Time, UTC+01:00)  #    Comments [0] -
Office2007
 Sunday, July 16, 2006

Wrox has posted a video of a presentation by Scott Hanselman at a .NET user group. Scott is very passionate about productivity. How many times a day do you type 'otepad'? Watch the video and learn how you don't really have to.

Sunday, July 16, 2006 9:15:52 PM (W. Europe Daylight Time, UTC+02:00)  #    Comments [2] -
Coding | Tools
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The opinions expressed herein are my own personal opinions and do not represent my employer's view in any way.

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Alex Keizer
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