James' Blog

Single UNIX Specification Firefox search plugin

While poking around on the Single UNIX Specification web site, I noticed a link to a Firefox Search Plugin.

With this plugin installed, you can search for keywords in the SUS directly from Firefox. Very cool.

Emacs can do that

As an emacs user, I knew the butterfly command. I just don’t find it that useful.

Delta chains and packs

In a discussion on creating a git repo for the gcc code base, Linus describes how git uses delta chains and how they relate to packing.

In the same discussion Linus has additional low level explanation.

Now with RSS 2.0

With help from Andrew Cowie’s blog post Getting Blosxom to work… my blog now has a functional RSS 2.0 feed.

Validate your RSS and Atom feeds

If you have a feed for your blog, make sure it is valid by using FEED Validator.

Check the validity of my RSS 0.91 and RSS 2.0 feeds.

Git Cheat Sheet

Zach Rusin has created a very easy on the eyes git cheat sheet. This is very useful if you use some git commands only once in a blue moon.

Why volatile is practically useless

In the C/C++ programming language, data can be given the volatile qualifier. Typically, people think this is sufficient to prevent code ordering problems. Well, volatile does not do that.

Linus provided a great explanation of the problem on the lkml today. Definitely worth reading. Also, you should read Linux Kernel Memory Barriers from the kernel documentation.

Update 2007-10-14: Also check out the LWN article The Trouble with Volatile.

x86info Fixes Merged

Dave Jones got some spare time and merged in my first 3 x86info fix up patches:

There are a couple more patches I need to send Dave now that the first set have been merged.

Changing the Firmware project to use genext2fs instead of UML

At OLS2007 I went to Rob Landley’s Cross Compiling Linux tutorial where Rob introduced his Firmware Linux project. Unfortunately we ran out of time and didn’t actually get to using the cross-compiler.

Rob’s approach to cross-compiling packages is to build a native environment (using qemu) so that you don’t actually have to cross-compile packages. Cool idea!

Anyway, to build the root file system that qemu will use, Rob used UML (User Mode Linux) to step around the root privileges required for mounting the loop device. I had trouble getting UML going on my laptop so I wrote a patch that evening to use genext2fs to create the root file system. Just to show how slow I am at following through, I finally sent the patch to the mail list. We’ll have to wait and see if Rob likes it.

How to turn your neighbours off using your WiFi

Even though this is not really a security issue, be aware that if you leech WiFi access from somebody, the access point owner can control the data stream you get (and send!).

Upside-Down-Ternet is a funny example of what one guy did to his leeching neighbours.