OS X is version 10 of the Apple MacIntosh operating system . OS X was described by Apple as its first "complete revision" of the OS since the previous version is OS 9, with a focus on modularity so that future changes would be easier to incorporate.
What is the meaning of Mac OS X?
Mac OS X is a line of Apple operating systems (OS) included in every modern Macintosh (Mac) computer. It is the successor to the classic Mac OS 9. In March 2001, Apple released the first Mac OS X operating system to hit the market: Mac OS X 10.0 Cheetah. Mac OS X operating systems are based on UNIX.
What number is OS X?
The letter "X" in Mac OS X's name refers to the number 10, a Roman numeral, and Apple has stated that it should be pronounced "ten" in this context. However, it is also commonly pronounced like the letter "X".