As the official PlayStation blog indicates, the "Install Other OS" feature, whereby Linux could be installed, will be disabled with firmware version 3.21 for the the older PlayStation 3s. As the blog says, "Consumers and organizations that currently use the 'Other OS' feature can choose not to upgrade their PS3 systems," but access to the PlayStation Network, playback of PS3 titles and Blu-ray videos, and use of new features and improvements would then no longer be available. Even playback of DRM-protected videos stored on the local server will no longer be allowed.

The reason, according to Sony, is "security concerns." In January, iPhone hacker George Hotz released a hack that under Linux used signal disturbance on the bus as an attack vector to get to ring 0 and access to full memory space for an exploit on the PS3. Hotz's exploit was but a half hack in that he only circumvented the encryption SPU of the Cell processor. The encryption itself, which serves for copying games, remained uncracked, as the keys are hardcoded in the encryption SPU (also called the hypervisor), which the hack could not access.

Sony is selling the disabling of the "Other OS" feature as an advantage in that it "will help ensure that PS3 owners will continue to have access to the broad range of gaming and entertainment content from SCE and its content partners on a more secure system."

The implementation should be interesting from a legal standpoint, since Sony was explicit when it originally introduced the PS3 that it would provide the "Other OS" feature. As late as the end of February (thus, long after the Hotz hack), Sony was still making statements that the Linux functionality won't be removed from older PS3s.

Linux on PlayStations has been especially popular in the university realm, because PS3s can be chained pretty cheaply into performance-rich Cell chip clusters that rival the fastest and most energy efficient supercomputers.

Linux users can always appeal to the PlayStation "Ask a Question" site as to how Sony feels about such a stunted product undertaking.