The name "Mac OS X" uses the Roman numeral to signify both the version number 10 (following Mac OS 9) and its deep connection to Unix . The OS was born from Apple's 1997 acquisition of NeXT , the company founded by Steve Jobs during his time away from Apple. It is built on the XNU kernel , which combines technology from the Mach microkernel and FreeBSD. Core Architecture
Allows the OS to manage CPU time between apps, preventing one frozen program from crashing the entire system. Mac OS X
Ensures that apps cannot write into each other's memory space, further increasing stability. The name "Mac OS X" uses the Roman