The PS4, which is scheduled to be released in November at the delightful price of $ 400, appears to run an operating system called Orbis OS, which is a modified version of FreeBSD 9.0. FreeBSD is a free version of BSD Unix that is generally fairly compatible with most Linux applications, and to the untrained eye a BSD-based system looks a lot like Linux. In theory, with a bit of work, this means you could almost take a PS4 game and run it on a Linux PC — but don’t get your hopes up for some kind of Linux gaming renaissance.
This information comes from leaked photos of the second-generation development kit, which reportedly started shipping to game developers back in November 2012. The screenshots clearly show the GNU GRUB bootloader, with an option to boot into Orbis OS. Orbis, as you may already know, is the PS4′s codename [pre-order the PS4 from Amazon now]. After selecting Orbis OS, a modified version of FreeBSD with a bunch of PS4-specific libraries appears to load. From GRUB, developers can choose between a text-only console version of Orbis OS (primarily for debugging), or a full version with graphics and audio services loaded (i.e. actually playing the game).
It isn’t wholly surprising that Sony opted to construct the PS4 on top of a FreeBSD foundation: FreeBSD is one of the most mature and stable operating systems out there, and it’s licensed in such a way that Sony can use as much or as little as the code as it likes, and use it for commercial purposes without kicking any royalties back to the developers. Unlike Linux’s GPL license, which compels anyone who modifies the code to publicly release any changes they make, the BSD license allows Sony to do whatever it likes with the code; no matter how many changes it makes, Sony never has to share them. In general, BSD licenses are much more desirable for commercial enterprises. It’s also worth noting that the PS3 operating system, CellOS, is also rumored to be based on FreeBSD — if Sony already has extensive experience with FreeBSD, it would make sense to stick with it.
If the PS4 does indeed run a modified version of FreeBSD, we can draw some interesting conclusions. For a start, FreeBSD doesn’t have an official Catalyst driver — but the PS4 is powered by a GPU that’s very similar to the Radeon 7870. Presumably, AMD developed a Catalyst driver specifically for Sony. It would be a huge boon for non-Windows gaming if that driver was made available by AMD, but that’s probably too much to hope for. There’s also the possibility that, as with the initial release of the PS3, the PS4 might support other operating systems, such as Linux — but again, we wouldn’t get our hopes up. (See: Valve: OpenGL is faster than DirectX — even on Windows.)
On the Xbox side of things, incidentally, we have no idea what OS the Xbox 360 runs. We know that the Xbox One has one operating system that’s similar to Windows 8, but the gaming OS is shrouded in mystery. [Pre-order the Xbox One from Amazon.] There is a long-running myth that the gaming kernel is based on Windows NT — a myth that Microsoft steadfastly denies, instead claiming that the Xbox OS was built from the ground up. Who knows: Maybe the Xbox OS is based on FreeBSD as well.