Mac OS X

Mac OS X (pronounced /mæk oʊ ɛs tɛn/) is a line of computer operating systems developed, marketed, and sold by Apple Inc. As of 2008, every new Macintosh computer ships pre-loaded with the latest version of the system. Mac OS X is the successor to the original or "classic" Mac OS, which had been Apple's primary operating system since 1984. Unlike its predecessors, Mac OS X is a Unix-based operating system, built on technologies developed at NeXT between the second half of the 1980s and Apple's purchase of the company in early 1996. Version 10.5, while running on Intel processors, is certified UNIX 03.

The first version released was Mac OS X Server 1.0 in 1999, and a desktop-oriented version, Mac OS X version 10.0 followed in March 2001. As of 2008, five more distinct "end-user" and "server" versions have been released, the latest being Mac OS X v10.5 in October 2007. Releases of Mac OS X are named after big cats; for example, Mac OS X v10.5 is usually referred to by Apple and users as "Leopard".

The server edition, Mac OS X Server, is architecturally very similar to its desktop counterpart. However, it also includes several additional administration software tools to facilitate workgroup management or provide simplified access to common network services. These tools include a mail transfer agent, a Samba server, an LDAP server, a domain name server, and others. It is pre-loaded on Apple's Xserve server hardware, but can be run on most of Apple's computer models.

Apple also produces specialized versions of Mac OS X for use on three of its consumer devices, the Apple TV, the iPhone, and the iPod touch.

Source : en. wikipedia.com