A central processing unit (CPU), also called a central processor, main processor, or just processor, is the most important processor in a given computer. Its electronic circuitry executes instructions of a computer program, such as arithmetic, logic, controlling, and input/output (I/O) operations. This role contrasts with that of external components, such as main memory and I/O circuitry, and specialized coprocessors such as graphics processing units (GPUs).
Inside a central processing unit: The integrated circuit of Intel's Xeon 3060, first manufactured in 2006
EDVAC, one of the first stored-program computers
IBM PowerPC 604e processor
Fujitsu board with SPARC64 VIIIfx processors
A computer is a machine that can be programmed to automatically carry out sequences of arithmetic or logical operations (computation). Modern digital electronic computers can perform generic sets of operations known as programs. These programs enable computers to perform a wide range of tasks. The term computer system may refer to a nominally complete computer that includes the hardware, operating system, software, and peripheral equipment needed and used for full operation; or to a group of computers that are linked and function together, such as a computer network or computer cluster.
A human computer, with microscope and calculator, 1952
The Ishango bone, a bone tool dating back to prehistoric Africa
The Antikythera mechanism, dating back to ancient Greece circa 150–100 BCE, is an early analog computing device.
Charles Babbage c. 1850