Central processing unit: Difference between revisions

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The '''central processing unit''' ('''CPU''') is the portion of a [[computer]] system that carries out the [[Instruction (computer science)|instruction]]s of a [[computer program]], to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the [[Human brain|brain]] in the computer. The term has been in use in the computer industry at least since the early 1960s.<ref name="weik1961">{{cite paper | author = Weik, Martin H. | title = A Third Survey of Domestic Electronic Digital Computing Systems | publisher = [[Ballistics Research Laboratory|Ballistic Research Laboratories]] | url = http://ed-thelen.org/comp-hist/BRL61.html | date = 1961 }}</ref> The form, design and implementation of CPUs have changed dramatically since the earliest examples, but their fundamental operation remains much the same.

On large machines, CPUs require one or more printed circuit boards. On personal computers and small workstations, the CPU is housed in a single chip called a microprocessor. Since the 1970's the microprocessor class of CPUs has almost completely overtaken all other CPU implementations. Modern CPUs are large scale [[integrated circuit]]s in small, rectangular packages, with multiple conectingconnecting pins.

Two typical components of a CPU are the arithmetic logic unit (ALU), which performs arithmetic and logical operations, and the control unit (CU), which extracts instructions from memory and decodes and executes them, calling on the ALU when necessary.