According to images found at vgleaks, Sony's next gen console will run on an operating system called Orbis OS. The OS is a modification of FreeBSD 9.0 which is a variation of BSD Unix with no liscensing fees that's generally compatible with Linux applications.
What does this mean for the PS4? Aside from not having any associated royalties to pay out, FreeBSD is a well developed operating system used quite extensively for commercial endeavours as it can be modified 'till the cows come home and doesn't require any kind of public announcement regarding those changes. Of course, being fairly Linux compliant, there is always the possibility, however slim, that PS4 could have some kind of OthrOS feature, but the jury is still out on that rather controversial feature.
Orbis was the code name given to what Sony announced as PlayStation 4 back in February. Since then the console has gone from strength to strength, dominating Xbox One in public polls, opinion and pre-order figures with its consumer friendly approach to the core gamer.
Thanks to PSU member faaeng for the tip! Stay tuned to PSU for all things PlayStation.