central processing unit definition architecture, processor
(CPU, processor) The part of a computer which controls all the other parts. Designs vary widely but the CPU generally consists of the control unit
, the arithmetic and logic unit
, temporary buffers
and various other logic.
The control unit fetches instructions
from memory and decodes them to produce signals which control the other parts of the computer. These signals cause it to transfer data between memory and ALU or to activate peripherals
to perform input or output.
Various types of memory, including cache
, are often considered to be part of the CPU, particularly in modern microprocessors
where a single integrated circuit
may contain one or more processors as well as any or all of the above types of memory. The CPU, and any of these components that are in separate chips, are usually all located on the same printed circuit board
, known as the motherboard
. This in turn is located in the system unit
(sometimes incorrectly referred to as the "CPU").
A parallel computer
has several CPUs which may share other resources such as memory and peripherals.
The term "processor" has to some extent replaced "CPU", though RAM and ROM are not logically part of the processor. List of processors (http://lldn.timesys.com/complete_list_of_processors)