OS


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Os,

symbol for the element osmiumosmium
, metallic chemical element; symbol Os; at. no. 76; at. wt. 190.23; m.p. 3,045±30°C;; b.p. 5,027±100°C;; sp. gr. 22.57 at 20°C;; valence usually +0 to +8.
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Os

(chemistry)

OS

(1)

OS

(2)
[obsolete, ITS], an output spy. See "OS and JEDGAR".

OS

(operating system)
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.

OS

(Operating System) The master control program in a computer or mobile device. The O-S acronym has been part of the names of various operating systems. Microsoft used DOS for many years in the PC, and Apple used OS 8, OS 9 and OS X in the Mac. For the major functions operating systems perform, see operating system. Some of the operating systems in this encyclopedia that have O-S in their name are TOS, DOS, PC-DOS, MS-DOS, DR-DOS, Mac OS, Mac OS X, iOS, OS/390 and OS/400.