Plan 9 ported to the Raspberry Pi
Plan 9 developer Richard Miller has ported the open source Unix-like operating system to the Raspberry Pi mini-computer. Plan 9, which was originally developed primarily for research into distributed operating systems by Bell Labs, is still being developed at Bell Labs (now a subsidiary of Alcatel-Lucent) and a number of independent developers. The operating system extends the classic "everything is a file" philosophy of Unix to network objects without differentiating between local and remote resources.
The Plan 9 port for the Raspberry Pi is available as an image file that can be decompressed and copied to an SD card to be run on the device. Bell Labs provides documentation and a Plan 9 Newbie's Guide for users who want to get started with the operating system. The Raspberry Pi image is based on the 4th Edition of Plan 9 which was released 2002. While Plan 9 is still being actively developed at Bell Labs, there have not been many substantial changes in the code base since. The plan9front fork provides more regular releases for users wishing to try a version of the operating system with a faster release cycle, but that is not currently available on the Raspberry Pi.
Correction: An earlier version of this article misstated the development status of Plan 9 at Bell Labs.