The official Orbis OS is the core software that runs the PS4. It is a modified version of , a Unix-like operating system.
: Sony built Orbis OS on top of FreeBSD 9.0, a robust, open-source Unix-like operating system. FreeBSD was selected over Linux primarily due to its permissive licensing structure, which allows corporations to modify the source code heavily without being legally required to release their proprietary additions back to the public. orbis os iso