The Commodore PET ("Personal Electronic Transactor") was a home/personal computer produced from 1977 by Commodore International.

The initial model, PET 2001, was announced at the Winter CES in January 1977 and the first 100 units were shipped later that year in October.

The PET's 6502 processor controlled the screen, keyboard and any peripherals connected to one of the computer's expansion ports. The PET was essentially a single-board computer with discrete logic, driving a small built-in monochrome monitor with 40×25 character graphics.

Although the PET 2001 was fairly successful, there were frequent complaints about the tiny calculator-like keyboard, often referred to as a "chiclet keyboard" because the keys resembled the gum candy. The keyboard issues were addressed in the upgraded "dash N" versions of the 2001, which eliminated the built-in Datassette (cassette tape recorder) in favor of an external cassette recorder.

The "dash N" units included a much larger keyboard with a full stroke motion. Internally a newer motherboard was used, along with an upgrade from static RAM to dynamic RAM. Models were available with 8, 16, or 32 KB of memory, known as the 2001-8N, 2001-16N or 2001-32N, respectively.

Source: Wikipedia, "Commodore PET", available under the CC-BY-SA License.