The Commodore PET

The Commodore PET was the first computer introduced by Commodore Business Machines, an office equipment manufactuer, after their acquisition of MOS technologies (who had put out the 6502 processor and KIM-1 single board computer a year previously.)

The year was 1977, and many folks had put several hundred dollars 'up front' and waited for months in order to receive this machine. It was one of the most 'complete' portable all-in one systems for it's time, including such features as:

• built-in 9" CRT display (monochrome 25 lines of 40 characters)
• 6502 microprocessor
• 4 or 8 k of RAM memory
• built-in BASIC in ROM! (by a small company called MicroSoft!)
• parallel I/O and IEEE-488* interface ports
• 73 key keyboard w/numeric keypad**
• built-in cassette storage drive
• upper, lower case AND graphics character sets.
• sturdy metal enclosure***

Many industry historians claim the name 'PET Computer' was coined after the 'Pet Rock' which was a popular fad a year before, Commodore used 'PET' as an acronym for: Personal Electronic Transactor.

* The IEEE-488 was not fully realized until later via a ROM upgrade.
** The keyboard was smaller and more resembled that of a calculator and are usually referred to as the calculator keyboard.
*** Originally the PETs were to have rounded cases like the one above, but as an office equipment manufactuer it was easier (and cheaper at the start) for Commodore to produce folded steel cases in-house instead of ordering custom plastic ones.

In the inside cover there is this statement:

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The potentials of your PET are virtually limitless.
This booklet, by its very nature, is limited.
Many questions will arise that this booklet has not covered or even anticipated.

Write to us at Commodore Business Machines with your questions. We will answer many that you and other users will pose with a newsletter we'll be sending out from time to time to users. Or your answer may be incorporated in a booklet for which we will charge a nominal fee . . . but we will call this to your attention.

User Program
Commodore Systems
901 California Ave.
Palo Alto, CA 94304
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The manual is 38 pages long (with a few blank pages at the end for notes) and discusses such things as 'unpacking your PET and turning it on', using the keyboard, an overview of BASIC, using the cassette to load a program, pinouts, simple memory map, BASIC command reference, cleaning and troubleshooting your PET (mainly on replacing RAMs, my machine still has a spare RAM, in a plastic rail taped inside the cabinet)

I was fortunate to meet the author of the manual, Rick O'Lehr, who also had developed the diagnostic routines for the computer.

Note: the cover shows that rounded case on the PET, it is actually the prototype PET (the case was carved from wood!) Of course the models released were more angular metal ones, plastic housings did show up in later models but retained the angular appearance customers became accustomed to. The last of the PETs released that did have rounded cases were the European CBM 200 and 8296 models which were more realted to the CBM 8000 series then the 40 column PETs.

Again, this is another image of the prototype PET (you get a better view of the rounded corners of the cabinet). The "wood-grain" look on this unit was done with the help of contact paper - close examination of the photo reveals it wasn't the best of jobs. (Though I think it looks kinda cool matching the kitchen cabinets).

Other micros mentioned (and/or pictured) in the article were Heath H-8, Radio Shack (TRS-80, as of then unreleased as well as the PET pictured), Altair 8800, SWTP 6800, IMSAI SBC 8048, Processor Technology's Sol, Technical Design Labs' Z-80 Xitan, Compucolor, Digital Group, Cromemco's Z-2, Polymorphic's Poly 88, Vector Graphic's Vector 1+, OSI's Challenger System, and EPA's 6800 system.

The reporter, Richard Izui, described the various screen shots and uses for a PET (those currently possible and those that should come later). The center image is a PET graphic of the playboy bunny (I plan to reproduce it later.) . In the summary of the article "...As if that isn't enough, your PET can also teach languages and mathematics, store recipes and turn on appliances and temperature controls - all for $595. Our computer says it's a steal."

The PET as well as the other 'big' micros of the time (such as Apple, and Radio Shack) generated a ton of books, several magazines (many covering all the computers as well as some specific to certain brands.)

Cursor Cassette Magazine (a monthly collection of programs on cassette)
- Rat Run (early 3-D maze program)
- Dungeon (Graphics dungeon type game)
- Ouranos! (Weather War)
- Police!
- Cover #13 (fish tank)
- Cover #8 (space flight)
- Bonzo! (chutes and ladders!)

Some Cool Hardware for the PET:
- MTU Visible Memory Board (320x200 hi-res graphics)
There were some really cool drawing programs and games for this including a star trek styled Space War.
- Hal Chamberlin Synthesizer Board also sold by MTU. Only heard music from this one once, and man, what nice output!
- Kurta Digitizer Tablet (combined with the MTU board it was a nice early 1980s graphics experimenter)

Some of the best Magazines with PET info:
- COMPUTE! 1978 - around 1984
- MICRO: the 6502 Journal
- Kilobaud Microcomputing 1978-1982
- Creative Computing 1978-1982
- TPUG Newsletter (Toronto PET Users Group) newsletter, the TORPET.
- BYTE (Small Systems Journal) late 70s - early 80s
- Commodore Microcomputing
- Transactor Magazine