Tuesday, October 5, 2010

Summary of Technical Work

The software for the upcoming pilot with the Haitian Coalition has four main pieces.

The Main Stick Image

The software for the stick is largely completed, as the build scripts to create an image from the open1to1 harddrive files have been written. However, there are bugs with our implementation of casper and with the video drivers for the donated computers. The casper bugs are related to casper's autologin and autohardware check. Both of these interfere with a normal use case and slow boot time. 

There are four possible kernel arguments to resolve the driver issues, and the best approach to fixing this problem appears to be a syslinux.conf file which poses all of the options as selectable items. This means I won't have to rebuild every time I want to try a new approach.

The casper problems are more challenging. I haven't found good documentation for the purpose and contents of the scripts involved, and while they're written in BASH, this does not mean they are easy to read. Fortunately, other individuals on the internet have encountered similar problems, and there are some solutions posted. However, due to casper's role in the initial ramdisk image, modifying casper necessitates a lengthy rebuild from scratch.


The Fast Switch image.

Luke Faraone and I worked together to design a solution to allow for students to switch between computers in a lab very quickly. The basic premise is that as the students don't have access to modify the stick past their /home directory, a simple over-mounting of the /home from the persistent file should function to allow students to access all the files on their stick in a transparent manner.

For more information, see my notes at on SVN at http://open1to1.org/svn/trunk/build-scripts/fastswitch_notes.txt.

The Boothelper image.

As the BIOS of older machines, like many of the P4s we're using in our pilot, don't support booting from USB, some form of alternate bootloader is needed. For this purpose, we're using the "PLOP" Bootmanager, customized to detect USB devices and attempt to boot off them in a mostly-silent manner. The ISO image for this is available here.

One issue with this is that the boothelper does not support USB keyboards. As, in normal operation, no keyboard entry should be needed, this isn't really a problem. However, this makes debugging difficult.


The backup solution designed for this pilot is dropbox-based. Keep an eye out for a blog post about that soon!

In other news, the most recent image can be downloaded as an ISO from my sugarlabs page. This file has both Spanish, French, and Haitian creole language packs, as well as a plethora of educational software. The md5sum for this file is f6d8724693c90ac9b2b758b7730a5604.


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