Sunday, April 22, 2007

OK, I figured out how to customize DSL

OK, I figured out how to customize D.S.L. so that it has the DSA host keys and the software I need on the same mini-CD that DSL is on.

Basically, the DSL distribution is a simple ISO formatted CD with Rock Ridge extensions. The KNOPPIX compressed root filesystem is a single file that takes up the majority of the space in the DSL image.

The boot information is stored in files in boot/isolinux off of the root of the CDROM filesystem. The isolinux documentation gave me the exact incantation to give mkisofs in order to make an ISO image that can use isolinux to boot. Once I verified that it worked by burning a CD-RW (my laptop is about seven years old, but the built-in CDROM drive thankfullys read CD-RWs without problem), I then added some stuff to the DSL root:

  • An encrypted copy of my "portable media" ssh key
  • Bitmap versions of the "Vorpal" font I mentioned in my last blog, complete with a script to install this font (DSL doesn't have mkfontdir)
  • MaraDNS with a basic resolve-on-loopback mararc
  • A lot of my English lessons
  • All of my favorite music by Jonn Serrie and a song I did myself
  • The memtest x86+ utility, since one of my students has been having problems with her system rebooting at random times. And, yes, the problem was indeed her memory.

The music took up over 100 megs of space. Despite this, the CD has a working version of the Firefox browser (albeit the older and undoubtably insecure 1.0.6 release), a working mp3 player, a simple word processor (Ted) and Spreadsheet program (siag), and numerous other goodies.

It's a very good system for uploading or downloading files without me neeing to lug my laptop everywhere. I'm using this setup right now to type this in.

The system is not perfect. For example, since the X server simply uses VESA, it isn't very fast, and, more annoyingly, only has a refresh rate of 60hz which is a little hard on my eyes when using a CRT. Also, I wish DSL used a more recent version of Firefox, or, even better, a version of Konqueror embedded for the browser.

But, the DSL setup saved me a lot of time and effort setting up my own bootable CD for taking to cyber cafes.

- Sam