SteamOS is Now Available
Just as Valve previously announced, the first public version of SteamOS is now available at their repository. However, if you want to download it right away, it will be very problematic, as everybody tries to do the same. Fortunately, people at SteamDB have managed to provide an unofficial torrent download of SteamOS. It will take some time to download and test it, but in the meantime here is what has been announced in Valve's FAQ.
Just as expected from the initial Steam testing on Linux, SteamOS is based on Debian GNU/Linux (just like Ubuntu). Most of the system will be open source, only Steam and drivers will be closed-source parts of the initial install. While the system will boot to Steam by default, the desktop and root access is present for additional system customisation. Valve says that SteamOS is compatible with most of Debian drivers, packages and programs. By default SteamOS is configured to use 2 accounts – a more restricted steam account where Steam games will run and desktop account which can be configured for administrator access. Those accounts are local and separate from Steam logins while their privileges should limit the ability of malicious software to harm the system. Standard Debian update services will be used to update SteamOS automatically from Valve's repository.
The hardware requirement are very limiting at the moment for SteamOS 1.0 'Alchemist'. It is 64-bit only, which should not be a problem these days. 4 GB RAM is listed as a minimal requirement, which is relatively steep, although it is unlikely that the system itself will be using that much for itself alone. 500 GB hard disk also seems like an insurance to have enough space for installed games. The current version of SteamOS only supports Nvidia's GPUs, which limits the first batch of testers. If it is only a driver issue, it will be easy to fix for users themselves, but considering AMD's current Linux drivers, the performance will not be as good as it should. Finally, only UEFI boot is supported, so recent motherboards are required to run SteamOS. There is also NO DUAL BOOT at the moment, so do not install it on your main PC.
Overall, it is easy to see why Valve only recommends first release to those who are comfortable with Linux. Out of the box hardware support is limited and installing it will require some skills. Only 300 lucky people receiving their beta machines will be able to test SteamOS no matter how much or little they can do in Linux. For the rest of us it is time to do some testing of our own.