Linux raspberrypi 3.1.9+ #168 PREEMPT Sat Jul 14 18:56:31 BST 2012 armv6l The programs included with the Debian GNU/Linux system are free software; the exact distribution terms for each program are described in the individual files in /usr/share/doc/*/copyright. Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent permitted by applicable law. Type 'startx' to launch a graphical session Last login: Tue Jul 31 22:03:41 2012 from sunray-v480
The OS is Raspbian, a debian wheezy linux distribution for arm processors, with hardware floating point support.
It is such a low power device, it can be on at all time, and consumes less power than my workstation when powered off (which draws 4 watts due to power supply minimum draw to support LAN wakeup). Great for a test webserver, or a monitor (for an alarm system, for motion activated cameras and the like), for kiosks, information displays, for streaming audio and / or video and the list goes on. And it is stable:
pi@raspberrypi ~ $ uptime 12:33:22 up 18 days, 22:45, 1 user, load average: 0.00, 0.01, 0.05
In an hour and 15 minutes it will have been up 19 days. Not bad considering I installed the OS 19 days ago, and the Pis are still hard to come by...