On June 5, 1977, at the summer Consumer Electronics Show, Commodore had its PET 2001 personal computer on display after showing a prototype at the January 1977 show. Chuck Peddle said Commodore took its first distributor order on that day, giving Commodore a case for being the first of the 1977 Trinity to sell a prebuilt personal computer, or at the very least, the first to demonstrate a working unit, having done so in January. It cost $495, quickly raised to $595.
The 1977 trinity
Byte magazine dubbed the PET, TRS-80, and Apple II the 1977 Trinity, being a trio of prebuilt computers all released the same year, introducing a new product category. Both Commodore and Apple exhibited preproduction units to the public at the West Coast Computer Faire on April 15-17, 1977 in San Francisco.
The odd thing about the 1977 Trinity of the Commodore PET, Apple II, and TRS-80 is how entangled they were. Apple wanted Commodore to buy them, but they couldn’t agree on a price. Commodore wanted Radio Shack to sell the PET and demonstrated the units to them at the June CES.
In the end, all three went alone. And none of them could keep up with demand. Of the three, Commodore underestimated demand the most, only producing 500 units. All three of them had waiting lists at the end of the year.
Chuck Peddle and the Commodore PET 2001
The PET was the brainchild of Chuck Peddle, the lead engineer behind the 6502 processor. Peddle built a single-board computer called the KIM-1 to demonstrate the 6502 but he really wanted to build a proper computer around it. The KIM-1 was just a bare PCB with a keypad for data entry and a 7-character display for output, priced at $245. You could connect a cassette recorder and a terminal to it and use it as a general purpose computer, but Peddle envisioned something easier and friendlier.
After Commodore bought MOS Technology, Peddle convinced his new boss, Jack Tramiel, to let him build a general purpose computer. Working 20-hour days to meet a short deadline, Peddle produced a prototype in a wooden case with a $90 black and white television tube acting as a display. Commodore displayed this unit at the winter CES, but wouldn’t have its first units for sale until June.
The PET 2001 had a built-in monochrome monitor that could display 25 rows of 40-column text, a built-in cassette recorder for storage, a calculator-style chicklet keyboard, and 4 kilobytes of RAM. Its top flipped open like the hood of a car to service it, but it didn’t have internal expansion slots like the Apple II. Peripherals plugged into the back. It had an IEEE-488 bus that disk drives and printers plugged into when they became available in subsequent years.
The keyboard was a disappointment considering Commodore was a typewriter company. Later revisions had a full travel keyboard.
Microsoft BASIC on the PET
The PET had Microsoft BASIC built into ROM. Commodore negotiated a one-time license fee for Microsoft Basic, something Microsoft later regretted because it extended to the very popular C-64 and VIC-20. Gates wanted $3 per unit. Tramiel said, “I’m already married,” and insisted he would pay no more than $25,000 for a one-time perpetual license. When Peddle visited Microsoft in 1976, Gates told co-author Ric Weiland to just get rid of him and not waste time. Peddle returned with the one-time deal, paying $25,000 and the right to make modifications. The only stipulation was they had to share any changes they made back to Microsoft.
They didn’t even have to show the Microsoft name anywhere. 6502 Basic for the PET did have an Easter egg in it though. When you entered the command WAIT 6502,1 the computer would print MICROSOFT! at the top left of the screen, over the top of the startup prompt that said COMMODORE BASIC. Commodore removed it when they needed to free up space in the ROM for other purposes. Gates confirmed in 2010 he put the Easter egg in.
Under Gates’ original proposal, Commodore would have owed Microsoft $36 million just on C-64 sales alone. Jack Tramiel was arguably the last person to get the better of Bill Gates in a business deal.
In September 2025, Microsoft released the original 6502 BASIC code as open source.
The only Commodore computers to credit Microsoft for Basic were the Amiga and the Commodore 128. As part of the deal for Amiga Basic, Commodore had to credit Microsoft on all future computers, regardless of what CPU they ran. As a result, the Commodore 128 displays a 1977 Microsoft copyright on power up.
The meaning behind the Commodore PET name
Officially, PET was an acronym for Personal Electronic Transactor. But this was really a backronym. PET sounded friendly, and the pet rock fad was still a recent memory. Use of the name caused Commodore trademark issues in some countries, leading Commodore to name later machines in the line CBM rather than PET. But the name stuck rather well. I recall seeing references to PET computers, without the Commodore name, well into 1984.
The Commodore PET in popular culture
TRS-80 was a great name, albeit one with an expiration date. The Apple II became iconic, partly because Steve Wozniak is affable. Sometimes it feels like the PET took a back seat to the two of those in popular culture, partly because Commodore was notoriously uninterested in product placement as part of its marketing strategy.
So imagine my surprise when I spotted an image of a PET in a record store, of all places.
The cover of the 1982 New Wave record Homosapien by Pete Shelley, the debut solo album from the former lead singer of the Buzzcocks, depicts Shelley sitting next to a Commodore PET computer and a telescope, surrounded by various objets d’art. In the music video for the title track from the song, the PET is powered on and running a program scrolling diagonal lines across the screen from the bottom left to the top right. If you want an offbeat collectible for your vintage computer collection, that album is affordable on Ebay.
The PET’s graphics characters
The graphics characters that made the visual effect in Shelley’s music video possible have a story behind them. Leonard Tramiel says they were his idea, he wanted the PET to be able to do two things: play card games and draw the Starship Enterprise from Star Trek, so they designed an extension to the character set to be able to draw the Starship Enterprise and to draw playing cards.
Bill Gates says the graphics characters were his idea, that he suggested Commodore add them so the PET would have graphics capability. Given Gates’ lack of interest in Commodore in general, this seems like a really odd thing for him to take credit for. I think Gates suggested the idea, not knowing Commodore was already planning to do it.
The Commodore PET’s legacy
The PET wasn’t as enduring as the Apple II and didn’t sell as well as the TRS-80. But it lent its architecture to future Commodore machines. The very successful VIC-20 and Commodore 64 used the same architecture with newer chipsets. With only 1 MHz and a maximum of 64K of RAM to work with, the machines couldn’t abstract away their differences with device drivers and maintain full compatibility. It was possible to write software that could run on any Commodore 8-bit machine, but it took effort.
David Farquhar is a computer security professional, entrepreneur, and author. He has written professionally about computers since 1991, so he was writing about retro computers when they were still new. He has been working in IT professionally since 1994 and has specialized in vulnerability management since 2013. He holds Security+ and CISSP certifications. Today he blogs five times a week, mostly about retro computers and retro gaming covering the time period from 1975 to 2000.