Computer

The computer, or as the French say, l'ordinateur, is a device that computes. Especially, say, a programmable electronic machine that performs high-speed mathematical or logical operations or that assembles, stores, correlates, or otherwise processes information. Computers have a central processing unit, and will often come in a variety of form factors and colors.

Definition
For encyclopaedic purposes,  defines a "computer" as a Personal Computer. In essence all video game consoles are computers, each capable of logical operations, but a Personal Computer differs because it offers a full Keyboard & Mouse setup, in addition to a few other customization aspects that most consoles do not offer.

Similarly for arcade games, arcade system boards are also technically computers and were precursors to the upgradable nature of modern PC systems, but they differ in the sense that they are dedicated game machines, whereas personal computers are general-purpose machines that can be used for practical as well as entertainment purposes.

Digital circuits
In the 1930s, Japanese NEC engineer Akira Nakashima introduced switching circuit theory. In a series of papers published from 1934 to 1936, he formulated a two-valued Boolean algebra, which he discovered independently, as a way to analyze and design circuits by algebraic means.

Nakashima's work was later cited and elaborated on by American engineer Claude Shannon, who showed a one-to-one correspondence between the concepts of Boolean logic and certain electrical circuits, now called logic gates, which are now ubiquitous in digital computers. He showed that electronic relays and switches can realize the expressions of Boolean algebra. The work of Nakashima and Shannon laid the foundations for practical digital circuit design, providing the mathematical foundations and tools for digital system design in almost all areas of modern technology.

Mainframe computers
The first electronic transistor computer was built in the United Kingdom, by the University of Manchester in 1953.

Early electronic transistor computers were initially not stored-program computers. The first transistorized stored-program computer was the ETL Mark III, developed by Japan's Electrotechnical Laboratory. It began development in 1954, and was completed in 1956.

Microprocessors
The first single-chip microprocessor central processing unit was the Intel 4004. It originated in Japan with the "Busicom Project" as Masatoshi Shima's three-chip CPU design in 1968, before Sharp's Tadashi Sasaki conceived of a single-chip microprocessor, which he discussed with Busicom and Intel in 1968. The Intel 4004 was then designed and realized as a single-chip 4-bit microprocessor in 1970, by Intel's Federico Faggin and Busicom's Masatoshi Shima.

The first 8-bit microprocessor was the Intel 8008 in 1972. It was followed in 1974 by the Intel 8080, a more general-purpose 8-bit microprocessor designed by Federico Faggin and Masatoshi Shima.

The first single-chip 16-bit microprocessor was introduced in 1975. Panafacom, a conglomerate formed by Japanese companies Fujitsu, Fuji Electric, and Matsushita, introduced the MN1610, a commercial 16-bit microprocessor. According to Fujitsu, it was "the world's first 16-bit microcomputer on a single chip".

Personal computers
The invention of the microprocessor led to the development of microcomputers, also known as personal computers. The first microcomputer was Japan's Sord SMP80/08, developed in April 1972. It was soon followed by several other unique hobbyist systems.

The first commercial microcomputer kits were based on the Intel 8080: the Sord SMP80/x series, released in May 1974, and the Altair 8800, introduced in 1975.

The first pre-assembled desktop home computers to come equipped with monitors appeared in 1977: the Apple II, the Sord M200 Smart Home Computer, and the Commodore PET.