Within the market of desktop and laptop computers, it is the second most widely used desktop OS, after Microsoft Windows and ahead of all Linux distributions, including ChromeOS. It is the primary operating system for Apple's Mac computers. MacOS ( / ˌ m æ k oʊ ˈ ɛ s/ MAK-oh- ESS ), originally Mac OS X, previously shortened as OS X, is an operating system developed and marketed by Apple Inc.