SteamOS is a Debian Linux kernel-based operating system in development by Valve Corporation designed to be the primary operating system for the Steam Machine game consoles. It was initially released on December 13, 2013, alongside the start of end-user beta testing of Steam Machines.
During a panel at Linux Conin 2013, Valve co-founder and executive director Gabe Newell stated that he believed "Linux and open source are the future of gaming", going on to say that the company is aiding game developers who want to make games compatible with Linux, and that they would be making an announcement the following week related to introducing Linux into the living room.
On September 20, 2013, Valve posted a statement on its website titled The Steam Universe is Expanding in 2014 which teased three new announcements from them related to "even more ways to connect the dots for customers who want Steam in the living-room."The first announcement was revealed on September 23 as SteamOS, with Valve saying they had "come to the conclusion that the environment best suited to delivering value to customers is an operating system built around Steam itself."A large focus of the reveal was the openness of the operating system, with it being announced that users would be able to alter or replace any part of the software, and that it would be free.
What are the hardware requirements SteamOS ?
Processor: Intel or AMD 64-bit
Memory: 4 GB or more of RAM
Hard Drive: 500 GB or more free space
Graphics: NVIDIA Graphics Card AMD graphics card ( Radeon 8500 or higher) Intel Graphics
Additional: Support for UEFI Boot USB port for installation
If you want to install only Steam gaming client then here it is explained step by step Steam gaming client installation in Ubuntu/Linux Mint.
Install Steam Client In Ubuntu/Linux Mint And Play Amazing Games On Linux