The Commodore PET (Personal Electronic Transactor) was a home/personal computer produced from 1977 by Commodore International. A top-seller in the Canadian and United States educational markets, it was Commodore's first full-featured computer, and formed the basis for their entire 8-bit product line. The PET has a special place in the history of micro-computers, as it was one of the biggest sellers in the 1979/1980 period, when computers were aimed at both the home and business market. Many people instantly recognise the PET as it stood out from the usual ' terminal plus box' computer.

The PET 4000 series was the final version of what could be thought of as the "classic" PET. This was essentially the later model 2000 series, but with a larger black-and-green monitor and a newer version of Commodore's BASIC programming language, Basic 4.0. The Commodore PET 4008 was the base model of the 4000 series with just 8K of RAM. It offered BASIC 4.0 as standard and a lower price point that made them attractive to schools.

The PET 4000 series was released in May 1980, three years after the original PET 2001. Although it has the same MOS 6502 CPU, running at the same speed (1MHz), improved circuitry allowed the 4000 series to run substantially faster. Other improvements included more memory and a better keyboard.

4008 refers to 40x25 character display. The 4000 series was available with either 8K, 16K or 32K; this example in our collection is the 8K model, hence the 4008. It has four ports. An eight-bit parallel port, a port for a cassette recorder, a port that brings out the system bus, and an IEEE-488 port. Still in use today, the IEEE-488 bus is relatively complex, allowing up to 15 devices on the bus, but is mostly used for laboratory and scientific instruments.

By this point Commodore had noticed that many customers were buying the "low memory" versions of the machines and installing their own RAM chips, so the 4008 and 4016 had the sockets punched out of the motherboard.

Commodore also released the CBM 8000 Series at about the same time as the PET 4000 Series. The 8000 Series is almost identical, except for having a 12-inch screen as standard instead of the 9-inch screen, displaying 80 characters per line of text.

Commodore apparently had legal issues with the "PET" abbreviation, and had to change it to something else. They chose "CBM", for Commodore Business Machines. It seems that in Germany, in 1976, there was already a PET - a "Programm Entwicklung Terminal", or "Programmer Development Terminal", based on a Philips X 1150 data pooling system.

Manufacturer: Commodore
Date: May 1980

This exhibit has a reference ID of CH43250. Please quote this reference ID in any communication with the Centre for Computing History.

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