Month: February 2010

Version Control Tools Is More Than Just The Tools

Martin Fowler has an excellent post on Version Control, and he almost got all of the way there, but for more than just a tiny development shop I think he missed a few important pieces.

http://martinfowler.com/bliki/VersionControlTools.html

Martin does say that Mercurial and git get most of the attention and that the choice between the two come down to “…the shadow of github.”

He is dead right, but I’d argue that this is where the recommendability starts. github is awesome. Ask anyone who has used it and I’ve rarely heard anything negative said. But for anything but the tiniest organization outsourcing your VCS to github is not a practical option. There could be IP requirements or legal requirements about keeping source private and just the over cautious nature of people is to want to run VCS in house. github is not open source. gitorious is.

http://gitorious.org/about

You can go checkout the source code to gitorious and run your own in your own internal organization. AWESOME!

I’d never heard of the Mercurial hosting project http://bitbucket.org/ until i read Martin’s post. That is great to know that it exists. But…

The most mature solution is something which is also open source, has the best project management implementation, has the best bug tracking implementation and integration and is just all around awesome. Its called Launchpad.

http://launchpad.net/

Yes, the same software that drives launchpad is open source and you can install and run it for your own team, company, organization or however you are structured.

Launchpad is written by open source volunteers as well as employees of Canonical. You can buy support for Launchpad from Canonical. Launchpad uses the lesser known bazaar DVCS. Martin kindly left out the DVCS which is used by the most prominent Linux distribution, ubuntu, and the most prominent open source database software, MySQL.

Just like GIT is not going away, because linux uses it, and Mercurial isn’t going away because python and google use it, bazaar is not going away, because ubuntu and mysql use it.

My point is that the web hub to your code and the tools surrounding how you get to your code is just as important as the base DVCS tool itself. SVN has always been good, but ViewVC makes it great. GIT is good. github makes it great. Launchpad makes bazaar great. It makes bazaar at least as good of a choice as either git or mercurial.

double.IsNaN is 100 times slower

Its not just your programming group that can’t get it right. I work in a semi-disfunctional group on contract for a client who, not matter how hard we try, doesn’t seem to listen to basic software engineering principles.

I feel a little better (and a great deal worse after thinking about it) when I see that the largest software company in the world deals with some of the same problems.

I found this gem in the WPFToolkit (it is MSPL) source.

// The standard CLR double.IsNaN() function is approximately 100 times slower than our own wrapper,
// so please make sure to use DoubleUtil.IsNaN() in performance sensitive code.
// PS item that tracks the CLR improvement is DevDiv Schedule : 26916.
// IEEE 754 : If the argument is any value in the range 0x7ff0000000000001L through 0x7fffffffffffffffL
// or in the range 0xfff0000000000001L through 0xffffffffffffffffL, the result will be NaN.        
public static bool IsNaN(double value)
{
    NanUnion t = new NanUnion();
    t.DoubleValue = value;

    ulong exp = t.UintValue & 0xfff0000000000000;
    ulong man = t.UintValue & 0x000fffffffffffff;
    return (exp == 0x7ff0000000000000 || exp == 0xfff0000000000000) && (man != 0);
}

 

My jaw was open pretty far for quite a few seconds as I read this.