The master control software system that serves as a foundation for applications software. Examples of past, present, and forthcoming operating systems include MS-DOS, Amiga DOS, Windows, Windows 2000, Windows Chicago, Windows Cairo, OS/2, Workplace OS, Apple/Mac Systems 7 and 8, Taligent (Pink), PowerOpen, NEXTStep, Rhapsody, Unix, SCO, AIX, HP/UX, HP/MPE, SCO Open Desktop, Solaris, and UnixWARE (Novell). A second class of operating systems is known as real time processing. These are used more for on-the-fly control systems such as aviation control systems and military applications. Examples include the Intel Multibus and iRMX operating systems. For a comparative analysis of the 32-bit options, see PC/Computing Special Report (1994) where it is concluded that there are advantages and drawbacks of each option and no clear optimal choice at this juncture in time. For 10 years, Apple Corporation would not license its proprietary Mac operating system to other manufacturers. However, in 1994 Apple announced that it would license its System 7 operating system to other vendors on PowerPC computers. In 1997, plans for Copeland and Gershwin upgrades were abandoned in favor or Rhapsody . Apple's hopes are riding heavily upon the evolution of a new operating system called Rhapsody that is a revolutinary operating system based upon NEXTStep technology. This may help to overcome the problem that Apple Corporation's market share has declined to less tan 5% of the desktop computing market and an even smaller percentage of the laptop/notebook computer market. The new licensing agreement is designed to cut into the huge market share of Windows operating systems from Microsoft Corporation. However, Microsoft Windows still remains the market share choice. Then along came Linux to challenge the Microsoft's operating systems. Linux (pronounced Leenicks) is a freely-distributable implementation of UNIX that runs on a number of hardware platforms, including Intel and Motorola microprocessors. It is very popular among computer scientists who have freely given their time to develpment of Linux. AThe Linux home page is at http://www.ssc.com/linux/ . (See also Cross-platform , Amiga , Windows , DOS , Windows Cairo , Windows Chicago , Windows 2000 , Mac , Alpha processor , Mozart , Copeland , Gershwin , Native , OS/2 , Wintel , and Rhapsody .)
Apple Corporation's operating system for its Mac OS X servers is called "Darwin." Apple announced that it will make the Darwin source code available to developers. It is a variant of UNIX.