Microsoft may have failed to occupy the stand it booked at this year's Linux Expo in London's Olympia conference centre, but some of the company's products did make a showing, even if the company might rather they had not.
On the stand of a multimedia-oriented Linux distribution called dyne:bolic, operating system author and maintainer Jaromil -- the moniker he prefers to be known by -- was demonstrating a hacked Xbox that can be used to offload processing tasks from a mixed cluster of PCs and Xboxes.
Although clustering Xboxes sounds an unlikely application, some organisations are investigating the computing possibilities of today's powerful games consoles, which tend to be smaller, cheaper and less power hungry (and therefore quieter) than PCs.
The National Center for Supercomputing Applications (NCSA) in Illinois has built a 65-node Linux cluster with PlayStation2 consolesto explore their application in scientific computing and high-resolution visualisation. The PS2's Emotion Engine CPU has two vector units designed to manipulate 3D polygon graphics for gaming, and Sony's Linux Kit provides programmers direct access to these.
Xbox clusters require the openMosix Linux kernel extension. "As soon as the processes use up the power of an Xbox or PC, the software looks for another machine on the LAN with more spare cycles, and sends the next process there to run," said Jaromil. The cluster behaves like a symmetric multi-processor machine, and can scale to well over a thousand nodes, according to the openMosix Project.
Microsoft does not provide any way of installing Linux on the Xbox, a feat that can only be accomplished either by chipping the console or by using exploiting a bug such as one in the MechAssault game, which is published by Microsoft. "Running the Xbox as a stand-alone machine isn't great, because it doesn't have much memory" said Jaromil. "But for clustering, it works really well. This Christmas you'll be able to get an Xbox for just over £100, so you could build a large cluster very cheaply."
Microsoft raised a storm recently when it began updating Internet-enabled Xbox game consoles with a software patch that blocks users from installing Linux on the console via the MechAssault bug. Aside from the fact that the updates deleted data from users' hard disks, the policy raised important questions about whether and how vendors should be allowed to tamper with hardware once it has been sold.
But the developers are fighting back. Even if Microsoft does manage to close the software bug, the controls that prevent Linux from being loaded can still be evaded in hardware. "You can still chip the Xbox," said Jaromil. "In a shop in Napoli (Jardmil is Italian) you'll always be able to get an Xbox chipped." Furthermore, he said, there are attempts by the hacker community to produce its own CD containing the software bug. The only catch is that the CD would have to be digitally signed, or authorised, by Microsoft. "There are people trying to get a buggy CD signed by Microsoft using social engineering techniques," added Jaromil.