The Mac OS is an operating system that was designed for the Apple computer. The Mac OS was developed by Apple Inc., the company that developed the Apple computer, as well as a number of other products including the iPod, iPhone, and iPad. The Mac OS is one of two major operating systems available, with the other being the Windows operating system.
The first version of the Mac OS, part of the “Classic” Mac OS series, was originally released in 1984. It did not possess a command line and could only run one application at a time. The first version of Mac OS to be named “Mac OS” was version 7.6. After multiple versions of the classic Mac OS series, the Mac OS X series of operating systems began to be released. Today (as of 2011), this is still the current series in production, with the most current version being OS X 10.7 Lion.
Operating system 