What is a CPU?


A central processing unit (CPU), processor or computer chip is the part of a computer in which operations are controlled and executed.

In other words the CPU is an essential piece of computer hardware which primary objective is to carry out the specific instructions that are required by computer programs.

To put this in a different perspective, if your computer system would be a human body the CPU can be seen as the part of the brain that deals with processing information.

A CPU consists of three basic elements namely: the arithmetic / logic unit (ALU), the control unit and the register areas.

The arithmetic / logic unit is the part of the CPU that carries out mathematical calculations and makes logical comparisons. The control unit is the part of the CPU that sequentially accesses the instructions of computer programs, decodes them and coordinates the stream of data within the ALU. The register area(s) are an area within the central processing unit that temporarily holds small units of computer program intructions and data before, during and after being executed by the CPU.

Primary storage or memory is closely related with the CPU. The computer’s memory contains the instructions of installed computer programs and data before or after they are processed by the register(s) within a CPU.

To better understand how instructions of the computer are being processed by the CPU, and how they relate to your computer’s memory have a look at the image below.

CPU process schematic
(Schematic image of the processing of information by a CPU)

Intel introduced the first modern commercial CPU, called chip 4004, on 15 November, 1971. The chip was originally created in collaboration with Busicom. The two computer companies their objective was to create a new programmable, general-purpose logic computer chip (Intel eventually bought the design and marketing rights of the 4004 chip from Busicom for 60.000 dollars, which soon after went bankrupt).

The chip’s design and construction team was lead by Federico Faggin and included Ted Hoff, Stanley Mazor and Masatoshi Shima. The four are regarded as the inventors of the first modern commercial computer chip, or central processing unit (CPU).

The co-founder of Intel
(Gordon Earle Moor, co-founder of Intel, 2013)

Gordon Earle Moore, co-founder of Intel, referred to chip 4004 as “one of the most revolutionary products in the history of mankind.”

During the same time period Intel produced it’s 4004 chip computer scientists at Texas Instruments and a range of other computer companies also developed a CPU, which all claim to be the true inventor of the modern commercial CPU.

Today the central processing unit (CPU) can be found in virtually every computer device around us, ranging from supercomputers to smartphones, desktop computers, laptops and tablets.


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  • Klooster, W. John. Icons of Invention: The Makers of the Modern World from Gutenberg to Gates, Santa Barbara: ABC-CLIO, LLC, 2009.
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Rowan Gonzalez

Founder & Chief Web Editor at Computer Stories
Rowan is the founder and Chief Web Editor of Computer Stories. He studied Communication and Multimedia Design at the University of Applied Sciences in Amsterdam from which he graduated in 2013. Rowan's passionate about computer technologies that make the world and our lives a little better.