This is just a rumor and it should be treated as such
A rumor about Playstation 4 that shows it running what it looks like a modified version of FreeBSD 9.0, has popped up online.The source of this information hasn't been verified, but Sony is not actually a stranger to the open source community.
As we can all certainly remember, Playstation 3 once had an option called OtherOS, which allowed users to run a Linux operating system.
That option has been removed from Playstation 3 and Sony took a hard PR hit. The images posted on neogaf.com, which are taken from VGLeaks, seem to indicate the operating system used in Playstation 4, Orbis, is actually based on FreeBSD 9.0.
“We have some details about the development of the Playstation 4 OS. The Operating System is called ‘Orbis OS’. It is a modified version of FreeBSD 9.0.
“We aren’t sure if this will bring again the ‘Other OS’ functions to Playstation 4 (remember that this option enabled Playstation 3 to install other OS in the console like linux or windows). When you boot up a second-gen development kit, you will be prompted with several options,” reads the post on neogaf.com.
Take this information with a large grain of salt and be sure to check out the images.