A
central processing unit (
CPU) is the
electronic circuitry within a
computer that carries out the
instructions of a
computer program by performing the basic arithmetic, logical, control and
input/output (I/O) operations specified by the instructions. The term has been used in the computer industry at least since the early 1960s. Traditionally, the term "CPU" refers to a processor, more specifically to its processing unit and
control unit (CU), distinguishing these core elements of a computer from external components such as
main memory and I/O circuitry.