The Steam Linux closed beta, which called for applications late last month, is now live. The Linux beta is available for installation on Ubuntu 12.04, since an "overwhelming majority" of experienced Linux applicants use Ubuntu, Steam says.

The Steam for Linux beta supports Team Fortress 2, though Steam has 25 games in total that run on Linux. Despite reports to the contrary in September, the beta includes Steam's controller-friendly Big Picture mode, which is also still in beta.

"This is a huge milestone in the development of PC gaming," Valve president Gabe Newell says. "Steam users have been asking us to support gaming on Linux. We're happy to bring rich forms of entertainment and our community of users to this open, customer-friendly platform."

Valve received more than 60,000 applications for the beta, and all beta rounds will come from this pool.