In 1975, Commodore acquired it’s microprocessor subsidiary MOS Technology, who brought with them designs for a computer kit based on their 6502 microprocessor. Deciding not to focus on building calculators, Commodore president Jack Tramiel ordered the design of a machine around the kit at the urging of designer Chuck Peddle. Commodore’s first full featured computer, the PET (Personal Electronic Transactor), was born.
The first model was the 2001, introduced in September 1977. It included either 4k or 8k of RAM. It was essentially the computer kit based around the MOS display chip, which supported a built in monochrome monitor. It also had a Datassette in the front of the case for storage. After being backordered for months, the 4k model was discontinued to ease the burden. It was very successful but many complained about the small keyboard, which had space sacrficed for the other parts of the machine which was all built into one unit. Later models made the Datassette external and included larger keyboards. Unfortunately the line was beaten by competitors such as the Tandy TRS-80 and Apple II, which offered color graphics.
The total cost of producing the PET, including shipping, was 1/70 of it’s price. The company also noticed users were buying the later model’s cheaper 4k versions and upgrading the RAM, so they punched out the extra slots in motherboards.