Valve's SteamOS is now available for download, as promised.
Valve announced earlier this week that it would ship Steam Machine prototypes to 300 beta testers and make SteamOS available for everyone to download on 13 December. That day has finally arrived; Valve just pushed the official repository.
SteamOS is an early first-look and public release, so it is not a finished product and therefore called a beta. If you’re still interested in trying it out, you can read more about it at Valve's website. You can then grab the official SteamOS APT repository or download an unofficial torrent for the installer at SteamDB.
Unfortunately, Valve wants people with no experience of Linux to wait before downloading and installing the new operating system: "Unless you’re an intrepid Linux hacker already, we’re going to recommend that you wait until later in 2014."
SteamOS beta uses Linux as an architecture, but Valve's development team has built on top. Plenty of hands-on reports should surface in the next few weeks, providing a more-detailed look at how it works, performs and feels.
The beauty of SteamOS is that it's free, and you won't need Valve hardware to install it. Valve also plans to make it a freely licensable operating system for manufacturers. So, think Android, in this regard.