stored-program computer

Table of Contents

Introduction References & Edit History Related Topics

Images

stored-program computer

computing

Written and fact-checked by The Editors of Encyclopaedia Britannica

Article History

Key People:: Tom Kilburn

Related Topics:: computer program

See all related content

stored-program computer, a computer that stores instructions in its memory to enable it to perform a variety of tasks in sequence or intermittently. The idea was introduced in the late 1940s by John von Neumann, who proposed that a program be electronically stored in binary-number format in a memory device so that instructions could be modified by the computer as determined by intermediate computational results. (Previous computers had their program instructions determined by the wiring of the machine or by holes on punched tape.) Other engineers, notably John W. Mauchly and J. Presper Eckert, contributed to this idea, which enabled digital computers to become much more flexible and powerful. Nevertheless, engineers in England built the first stored-program computer, the Manchester Mark I, shortly before the Americans built EDVAC, both operational in 1949.

The Editors of Encyclopaedia BritannicaThis article was most recently revised and updated by Erik Gregersen.

central processing unit

Table of Contents

Introduction References & Edit History Quick Facts & Related Topics

Images

central processing unit

computer

Also known as: CPU

Written and fact-checked by The Editors of Encyclopaedia Britannica

Last Updated: Apr 14, 2025 • Article History

Related Topics:: control unit; microprocessor; Pentium; Arithmetic Logic Unit; Intel 8088

On the Web:: University of Babylon - The central processing unit(CPU). (PDF) (Apr. 14, 2025)

See all related content

News •

Microsoft researchers say they've developed a hyper-efficient AI model that can run on CPUs • Apr. 16, 2025, 6:45 AM ET (TechCrunch)

central processing unit (CPU), principal part of any digital computer system, generally composed of the main memory, control unit, and arithmetic-logic unit. It constitutes the physical heart of the entire computer system; to it is linked various peripheral equipment, including input/output devices and auxiliary storage units. In modern computers, the CPU is contained on an integrated circuit chip called a microprocessor.

The control unit of the central processing unit regulates and integrates the operations of the computer. It selects and retrieves instructions from the main memory in proper sequence and interprets them so as to activate the other functional elements of the system at the appropriate moment to perform their respective operations. All input data are transferred via the main memory to the arithmetic-logic unit for processing, which involves the four basic arithmetic functions (i.e., addition, subtraction, multiplication, and division) and certain logic operations such as the comparing of data and the selection of the desired problem-solving procedure or a viable alternative based on predetermined decision criteria.

This article was most recently revised and updated by Erik Gregersen.