Valve has made it a little bit easier for gamers to experiment with SteamOS. The latest build adds dual-booting support, allowing users to run both SteamOS and Windows on a single machine. It also includes a utility that can install SteamOS directly from Windows.
The Windows installer can be found inside the downloadable ISO file containing the updated "Alchemist" build. This is the first time Valve has made SteamOS available a standard image file; previous releases have been packaged in ZIP archives that required a USB thumb drive to install. The ISO weighs in at just under 1GB, so it shouldn't take long to download.
Configuring a dual-boot setup can be done through SteamOS's "Expert Install" mode, which also includes custom partitioning options. Be careful, though. Valve cautions that the latest version of SteamOS has received "very little testing," and it recommends against installing the OS on "any machine you are not prepared to use." Now is probably not a good time to try dual-booting SteamOS on your primary PC.
The last major addition to the Alchemist release is support for systems that lack UEFI-compatible firmware. SteamOS now runs on machines with BIOS-based firmware, which covers a lot of older PCs. We didn't see UEFI-based firmware on desktop motherboards until Sandy Bridge arrived in early 2011. AMD motherboards took even longer to adopt the new firmware interface.
Interestingly, most of these updates come from the open source community. Valve credits the developers behind Ye Olde SteamOSe for many of the changes in the new build. It looks like that offshoot was the first to implement dual booting, partition resizing, and support for BIOS-based systems. Ye Olde SteamOSe also claims support for a wider range of networking and audio gear, but Valve doesn't appear to have picked up those enhancements just yet.