Archive for the ‘CodeProject’ Category

Gendarme Integration for VS2008

09:33 PM

Ever since setting up our CruiseControl.NET server for our internal projects, I wanted to integrate a Gendarme run to catch all those nasty little things that slip through, like not checking arguments for null.

Now that I finally found some tuits to do it, the next problem became obvious: doing a quick commit often lead to a quick build fail. Gendarme would have no use if it didn’t find anything, no? So the missing piece was integration into Visual Studio. Arthur hacked together a little XSLT+PowerShell and voila, Gendarme now runs on every build right from the studio and populates the “Error List” window with properly linked entries. Yay!

Read on for the details of the implementation. The complete source is downloadable at the end of the article.

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Posted in CodeProject, Microsoft, Open Source, Tech | No Comments »

MSSQL doesn’t (completely) support IEEE754 floating points

12:00 PM

After looking for quite a while (it is unbelievable, no?) I have to accept that Microsoft’s SQL Server 2000, 2005 and 2008 do not fully support IEEE-754 floating point numbers. Specifically NaN (Not-a-Number) and +/- Infinity are not allowed. While the 2000 Server seemingly allows such values to be inserted, but breaks badly afterwards, the newer versions disallow inserting such values. Here is the MS Connect article requesting the feature. There is also the documentation about float data and a read-between-the-lines hint in the documentation for XPath numbers. The article describing floats is very circumspect about this:

The behavior of float and real follows the IEEE 754 specification on approximate numeric data types.

[emphasis mine]

The XPath article states it clearly:

However, float(53) is not exactly IEEE 754. For example, neither NaN (Not-a-Number) nor infinity is used.

.

For completeness, here’s a little review about other DMBS’ support for NaNs and Infinity:

Posted in CodeProject, Microsoft, Open Source, SQL, Tech | No Comments »

Android development FAIL

04:25 PM

After installing the Android 1.5r3 SDK and Eclipse 3.4 with the matching ADT plugin, I soon encountered this error message:

[2009-10-16 15:02:09 - ddms]Failed to reopen debug port for Selected Client to: 8700
[2009-10-16 15:02:09 - ddms]Address family not supported by protocol family: bind
java.net.SocketException: Address family not supported by protocol family: bind
	at sun.nio.ch.Net.bind(Native Method)
	at sun.nio.ch.ServerSocketChannelImpl.bind(Unknown Source)
	at sun.nio.ch.ServerSocketAdaptor.bind(Unknown Source)
	at sun.nio.ch.ServerSocketAdaptor.bind(Unknown Source)
	at com.android.ddmlib.MonitorThread.reopenDebugSelectedPort(Unknown Source)
	at com.android.ddmlib.MonitorThread.run(Unknown Source)

[2009-10-16 16:29:40 - ddms]Can't bind to local 8600 for debugger
[2009-10-16 16:30:14 - ddms]Can't bind to local 8601 for debugger
[2009-10-16 16:30:14 - ddms]Can't bind to local 8602 for debugger
[2009-10-16 16:30:15 - ddms]Can't bind to local 8603 for debugger
[2009-10-16 16:30:25 - ddms]Can't bind to local 8602 for debugger
[2009-10-16 16:30:25 - ddms]Can't bind to local 8606 for debugger
[2009-10-16 16:30:25 - ddms]Can't bind to local 8607 for debugger
[2009-10-16 16:30:25 - ddms]Can't bind to local 8610 for debugger

As it turns out, the debugger tries to connect to “localhost” which is resolved by Windows Vista via the Windows\System32\drivers\etc\hosts file, which contains the IPV6 address “::1″. Since Android’s IPv6 support is still under development, none of the development tools can cope with it, resulting in above error messages.

Substituting the IPv4 127.0.0.1 as localhost address made it work fine.

Posted in Android, CodeProject, Open Source, Tech | No Comments »

Floating point adventures

12:27 PM

Using == to compare floats and doubles is not only problematic when dealing with numerical precision, but also when dealing with NaNs: In C#, the equals-operator returns false when comparing NaNs. If NaNs shall compare equal (e.g. when suppressing PropertyChanged events, as I’m doing), use Double.CompareTo(double). The IComparable<> interface requires that A.CompareTo(A) always returns zero and therefore does correctly (for this case) work with NaNs and +/- infinity.

Posted in CodeProject, Tech | No Comments »

Minor note on ‘dd’ write performance

11:12 PM

Today I was cleaning out some old logical volumes. Since they resided on rented harddisks, I chose to overwrite them with zeroes to avoid leaving data tracks on someone else’s disks. The first thing that came to my mind was this:

dd if=/dev/zero of=/dev/vg/lv

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Posted in Benchmarking, CodeProject, Open Source, Tech | No Comments »