Does this make me an Internet star?

I was reading the Wikipedia article about Ken Silverman's PNGOUT, which is a program for creating optimised versions of PNG images. However, it was the screenshot in that article that intrigued me the most. Upon further investigation, it seems that a group of Wikipedia users have been running a minor contest amongst themselves to create the most optimised version possible of an image I originally uploaded three years ago.

It's really weird when you stumble across things like this.

Syndicated 2008-09-26 01:04:47 from fragglet

c-algorithms 1.2.0

Version 1.2.0 of my C Algorithms library is up. The biggest changes in this release are the improvements to the test suite. I've written a bit about the test process that I've been using for improving the library.

Learning about coverage tools has been an interesting process. I liken writing tests without using coverage analysis to trying to optimise code without doing any profiling. With optimisation, it's easy to pick something that you think is a bottleneck and waste lots of time optimising it; in the same way, I've found that it's possible to write tests that you think are exercising the code in a satisfactory way, but actually aren't. Profiling helps to show exactly what's going on. In the course of analysing the library, I found a bug that should have been shown up in the tests, but wasn't, because the tests weren't exercising all of the code as I assumed they were.

Testing how code behaves in failure conditions is as important as testing how it behaves normally, so I wrote some code that uses #define macros to wrap the standard C allocation functions and allow the tests to simulate memory allocation failures. Again, coverage analysis is helpful here, too.

All in all, I'm not entirely sure why I'm writing a data structures and algorithms library, considering that all of these things have already been implemented hundreds of times over by different people. I originally wrote the library to remove the dependency of Irmo on GLib. Since then it's taken on a life and direction of its own, probably due to my own slightly obsessive nature. I think I just like the process of crafting something to the highest quality I possibly can.

(Also: Open source software with a test process? World coming to an end!)

Syndicated 2008-09-15 11:28:01 from fragglet

New screensaver

Large Hadron Collider + GLeidoscope = Large Hadron Kaleidoscope

Syndicated 2008-09-09 00:11:17 from fragglet

4 gigs of pain

We're rapidly reaching (or have reached?) the point where it's standard to have at least 4 gigabytes of RAM in desktop PCs. This presents an interesting dilemma, because most people run 32 bit operating systems; 32 bits doesn't allow more than 4GB of RAM to be addressed. The ideal alternative is to move to 64 bits; all modern CPUs support x86-64. Unfortunately, it requires a massive porting effort to get everything working on x86-64 (drivers from third party vendors are likely to be the biggest problem), so we're not quite there yet.

In the meantime, there's a useful feature called PAE which allows up to 64GB to be addressed by a 32 bit OS. I was surprised to see, however, that neither Windows XP or even Vista support it, although the server-based versions of Windows do!

The cynic in me wondered if this was a deliberate attempt by Microsoft to stop people from using the normal desktop version of Windows for running big servers, but this seemed a bit too much, even for them. But the Wikipedia article has the actual reason: "desktop versions of Windows (Windows XP, Windows Vista) limit physical address space to 4 GB for driver compatibility reasons".

So poor Microsoft appear to be stuck between a rock and a hard place. They cannot enable PAE, which is, in a sense, a backwards compatibility feature, because doing so would break driver backwards compatibility. This would appear to be an example of a situation where the Linux-style hatred of stable APIs wins over maintaining backwards compatibility. One part of the problem is that Microsoft relies on third-party vendors for drivers. They can't just update their platform and the drivers with it, because they don't have any control over them.

Syndicated 2008-08-04 11:59:27 from fragglet

Gnome 3.0

The Gnome 3.0 announcement is a win for sanity and demonstrates the maturity of the people running the project. There's an elegance about a project that aims to be boring-but-functional, rather than exciting-and-unstable. Rather ironic for a project that was once described as a "cascade of attention-deficit teenagers".

Syndicated 2008-07-15 20:55:13 from fragglet