Os

Os, symbol for the element osmium.

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operating system (OS)

Software that controls the operation of a computer, directs the input and output of data, keeps track of files, and controls the processing of computer programs. Its roles include managing the functioning of the computer hardware, running the applications programs, serving as an interface between the computer and the user, and allocating computer resources to various functions. When several jobs reside in the computer simultaneously and share resources (multitasking), the OS allocates fixed amounts of CPU time and memory in turn or allows one job to read data while another writes to a printer and still another performs computations. Through a process called time-sharing, a large computer can handle interaction with hundreds of users simultaneously, giving each the perception of being the sole user. Modern computer operating systems are becoming increasingly machine-independent, capable of running on any hardware platform; a widely used platform-independent operating system in use today on mainframe computers is UNIX. Most personal computers run on Microsoft's Windows operating system, which grew out of and eventually replaced MS-DOS. See also Linux.

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OS

See operating system.

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Os

(chemistry)

osmium

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1.		OS - operating system.
2.		OS - [obsolete, ITS], an output spy. See "OS and JEDGAR".
3.	(operating system)	OS - An operating system from IBM for their System/360 line of hardware announced in 1964. OS was planned with several flavours that were supposed to be compatible. OS was late, memory hungry and not able to reach the marketing objectives of IBM for the 360/30, the planned successor of the IBM 1401. IBM then decided to design a new operating system for the low end machines which they called DOS/360.