Computer History: From The Antikythera Mechanism To The Modern Era

The Era Of Microcomputers: ALTAIR 8800 And Other Early Computers

In 1973, only a few months after the release of the Intel 8008 CPU, the first non-kit microcomputer or personal computer (PC) was presented in France, and it used Intel's CPU. The Micral N PC wasn't commercially successful. That same year the Scelbi-8H PC was released, and was available either fully assembled or in a kit that the prospective buyers had to assemble. In 1974 the Mark-8 PC followed, which used the same Intel CPU as the Micral N and Scelbi-8H PCs.

Possibly the most famous of the early PCs is the Altair 8800, released in 1975, which was available pre-assembled and in a kit form. The Altair 8800 used the newly released Intel 8080 CPU and had 256 bytes of RAM. During the same year as Altair's release, two students, Bill Gates and Paul Allen, founded Microsoft and released a BASIC compiler for the Altair 8800, giving it its first programming language. This meant that anyone with an Altair PC could write its own programs, which was a real breakthrough.

Initially, the Altair could only be programmed through the switches on its front panel, and the output was given as a pattern of lights on its front. Later, its manufacturer added additional expansion cards that included a paper tape reader, RAM upgrades and an RS-232 interface, which allowed connection to a Teletype terminal.

Kenbak-1 And Micral N

The top computer in the photo above is the Kenbak-1, which is considered to be the world's fist personal computer. It was invented by John V. Blankenbaker of Kenbak Corporation in 1970, and the first unit was sold in 1971 for $750. In total, 50 Kenbak-1s were built. The PC didn't have a proper CPU and instead used TTL chips, because at this time the first microprocessors (TMS 1000 and Intel 4004) weren't invented yet!

The computer shown below the Kenbak-1 is the Micral N, which was made in France by Réalisation d'Études Électroniques (R2E) in 1973. This was the first commercial personal computer that used a CPU (Intel 8008). In addition, the Micral N, like the Kenbak1, didn't come in a kit but was pre-built.

IMSAI 8080

The IMSAI 8080 was released in 1975 and in its early version it used an Intel 8080 CPU. Actually, the IMSAI 8080 was an Altair 8800 clone, which was its main competitor. It was running the CP/M OS, which later evolved into the IMDOS operating system for the IMSAI 8080 computers. This computer became famous thanks to the WarGames movie (released in 1983), because the main character played by Matthew Broderick used an IMSAI 8080 along with a modem in order to hack a large supercomputer. 

EPA Micro-68

The EPA Micro 68 was released in 1977 and used a Motorola 6800 CPU and had a six-digit and seven-segment display. You can learn more about this computer here.

System3, Smaky6 And SOL Terminal

In 1978 three personal computers were released, including the Cromemco System 3, the Smaky6 and the SOL Terminal. Cromemco was a highly successful company that also built the Cyclops digital camera, introduced in 1975, which was the first commercial all-digital camera featuring a MOS image sensor. The resolution of the digital sensor was 32 x 32 pixels or 0.001 Megapixels! Another noteworthy Cromemco product was the TV Dazzler, which in essence was a graphics card for S-100 bus (an early expansion bus type) computers. With this gadget a color TV could be used as a computer display, and more than one Dazzler card could be installed into a PC and synced together, driving equally numbered displays. Thanks to this feature Dazzler cards were widely used in weather display systems used by U.S. TV stations during the 1980s.

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Contributing Editor

Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.