Valve's plans to bring Steam to Linux have advanced further this week, with the publisher announcing details of a private external beta to test the digital distribution platform on the open-source operating system.

　　According to a post by the Valve Linux team, the internal beta will be starting next week, and will be followed by a private external beta for 1,000 users sometime in October (no set date has been confirmed).

　　Valve said that the private external beta will include Steam, one Valve game, and support for Ubuntu 12.04 and above, but will not include Big Picture mode or additional Valve games.

　　The Valve Linux team will be using a sign-up page for the external beta, which will be detailed in a future post.

　　Valve announced its plans to port Steam to Linux in July this year, revealing that it was starting with Ubuntu and a work-in-progress Left 4 Dead 2 port.

　　The project, which began in 2011, aims to bring Steam to work with a functioning Ubuntu build of Left 4 Dead 2. Valve's 11-person Linux team wants to make the game run on Ubuntu as well as it does on Windows, and plans to begin accommodating other distributions of Linux.

　　Steam on Linux would add yet another platform to Steam's base, which already includes presences on PC, Mac, PlayStation 3, Android, and iPhone.