The Amazing Commodore PET
by Ian Matthews of Feb 22, 2003

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Commodore PET History:
Announced and demonstrated in January of 1977 at the Consumer Electronics Show in Chicago, months before the Apple II or Radio Shack TRS80, the Commodore PET was the worlds first real computer. 

The PET came fully functional out of the box.  It had:

- a keyboard with a separate numeric pad (almost completely unheard of at the time, even as an option)
- a 9" integrated Blue and White monitor
- a main board with a powerful new 1Mhz MOS 6502 processor
- lots of room for an additional RAM or Processor board
- 4K of memory
- power supply
- real storage device (cassette tape)
- several expansion ports including an RS232 (serial) port
- ability to handle and create fantastic graphics
- upper and lower case text
- an operating system that was burned onto ROM and loaded on boot... WOW that was cool.

all wrapped up in a solid and good looking, white chassis.  The prototype PET's chassis use rounded edges that were designed by Porsche.  When it came to production time,  Commodore decided to use the now familiar square cases, to keep production costs down.

All previous home and small business computers were little more than circuit boards; some of which did not even come with power supplies.

The original PET demonstrated at the Consumer Electronics Show had been cobbled together in a hurry and on the cheap.  It had a chassis made of wood and a picture tube taken from a $90 black and white TV that MOS bought from a local hardware store.  Chuck Peddle spent three days without much sleep getting the machine ready for the show and did not complete his now historic task more than a few hours before it began. 

A year earlier, in the spring on 1976 MOS Technologies' Chuck Peddle completed development of the versatile and very inexpensive MOS 6502 processor.  He and his largely ex-Motorola colleagues developed the KIM1 "Computer Trainer" to show off the functionality of this new chip but it was only the start.  Chuck developed the PET concept and took it to Radio Shack hoping to have them retail it for him but they were not interested.  Soon after, in the summer of 1977, Commodore's founder Jack Tramiel took a three million dollar loan guarantee from Canada's Irving Gould and immediately bought MOS Technologies, its staff, its patents, it production facilities, and the PET concept.

At the time Commodore manufactured office equipment like filing cabinets but its biggest business was calculators so it is no surprise that the original production Commodore PET 2001's had sheet metal chassis and calculator style keys which were dubbed chiclet keyboards.  These 47 pound beasts were all manufactured in Commodore's original (and short lived) U.S. facility located in Palo Alto California. 

There are several rumours about the source of the name PET.  Officially it was an acronym for Personal Electronic Transactor, but P.E.T. are also the initials of one of Jack Tramiel's relatives (his wife I believe).  Whatever the origin, Jack thought that PET sounded better and may have some positive linkage with the Pet Rock fad of the late 1970's.

The PET made the cover of the October 1977 Popular Science,  had a small write up in a 1978 Playboy and had a very interesting and detailed review from the cover of the February 1978 Electronics Today. 

During the first few months Commodore could only produce about 30 machines per day but they had a huge demand.  Commodore managed to assemble a miger 500 machines in its first year. 

The four kilobyte PET's (yes that is 4096 bytes which equates to a whopping 4096 characters!) were offered through mail order for $495 and a three to six week wait. Immediately orders starting pouring in and so Jack Tramiel quickly adjusted the price to $595.  At the same time the $795 8K model was actively promoted and the 4K model was downplayed.  I believe they did this by indicating that 8K machines would ship MUCH faster than 4K machines. 

When Commodore expanded to Europe in 1978 Jack doubled the price for the same machine under the Commodore PET 3008 3016 and 3032 badges.  As was almost always the case in those days, Jack was right; the 3000 series and related future models were highly successful.

The COMMODORE BASIC Operating System was written by Bill Gates and Paul Allen from their fledgling Micro-Soft Corporation (later renamed to Microsoft Corporation).  Commodore Basic was the only software license ever granted by Microsoft to any company for all products regardless of the number of copies used.  Commodore went on to produce literally millions of machines with various forms of Commodore Basic and did not pay Microsoft a single cent after the initial licence purchase in 1976/7. If anyone knows how much this licence cost Commodore I would love to know so please send me an email.

The PET was a hit and in the early days, Commodore was receiving as many as 50 requests a day from small would be computer stores that wanted to sell the PET.  Jack was in the luxurious position of being able to pick and choose his dealers.  He insisted all stores have:

- a good history
- a retail store front
- an in store service technician
- a parts inventory, and most importantly
- pay Commodore a cash deposit in advance for all orders

Within a year Commodore had enough negative feedback about their chiclet keyboard that they decided to introduce a standard keyboard model.  To accomplish this they had to remove the integrated cassette tape drive.  Just after that, the expensive metal cases were replaced with plastic cases. By 1980 the PET  had a massive 12" black and white monitor version which later became standard.

I recall buying my Commodore PET 4016 with 9" screen, tape drive and a 2031 170K single floppy drive for about CDN$2000 from my local dealer in Belleville, Ontario in about 1980. I still own that equipment and all devices work like the day they left the factory - click on the PET keyboard picture on the right. Note that at the time Canadian $ were just better than PAR with American $ and that Commodore was a Canadian company with serious operations in Toronto, just a two hours from my house.

Commodore developed many revisions of the PET hardware and firmware, perhaps the most interesting of which is the SuperPET.  Using Ontario Canada's University of Waterloo, Commodore developed the worlds first "co-processor computer". The Commodore SuperPET was a standard Commodore PET 8032 with 6502 processor, plus an expansion board that carried a 6809 processor and 64K more memory.  In fact there was an $795 upgrade kit to convert your 8032 to a SuperPET.  There were two small toggle switches under the right side of the chassis to change which CPU was in use and in what mode the machine was to operate.  The SuperPET ran Waterloo MicroAPL, MicroFORTRAN, MicroBASIC, MicroPASCAL, MicroCOBOL in addition to the standard Commodore Basic version 4.  It was to be used primarily by scientists or students to work off-line from the company's or school's mainframe and then connect and upload whatever was achieved while off-line (i.e. debugged APL code, processed data...).  Truly an innovative machine for the low low price of $2795.

By 1982 PET sales were declining with increased competition and Commodore decided to refresh the line with what Commodore called the CBM-II line: the B and P Series were conceived.  These machines came in many different configurations including ones that did not have integrated monitors.   These were the first production computers to sport the snappy Porsche designed round case.

The P or Personal Series machines were demoed at trade shows and a small number of Beta machines were released to Canadian and American dealers to show to prospective clients what they could do.  Unfortunately the dealers started to sell these demo machines.  Beta means pre-release and not finished.  As such these machines were buggy and got a bad name before they were ever released.  Commodore also thought that the new P Series would cut into their exploding Commodore 64 business so they cancelled the P before it was every officially released.  The remaining P128 inventory was plowed under in a land fill.

B or Business Series machines on the other hand were released in both North America and Europe.  A top of the line Commodore B had:

- two integrated 5.25" drives with a 1MB of capacity (in 1983!)
- 128K of RAM expandable to a mind boggling 1MB
- powerful 6509 CPU at 1Mhz
- potential access to almost every piece of PC software on the planet (see below)
- Zilog Z80 co-processor board that would allow MS DOS 1.25 and CP/M-86 programs to operate
- there are only three known 8088 cards in known existence today
- the only programs that were ever developed to run on these cards were "MS-DOS 1.25 for Commodore B Series" and a developer version of CPM-86 (i.e. no real software)
- the remarkable Commodore SID sound chip
- high resolution graphics
- separate keyboard
- integrated 80 column, 12" Display with swivel base (the P Series was colour!)
- integrated Commodore Basic Version 7
- a smooth, round, sexy case designed by Porsche... still today the best looking computer ever produced

Even with all this functionality, Commodore still not sell the B Series PET's.  They only produced a very small number of business applications for the B.  Commodore refused to support any of its products with much advertising and at a time when other world wide companies like IBM had an advert in every magazine and every night on TV, from the start the B was doomed.  Most B Series were sold in Europe, including the West Germany manufactured C710 'high boy' that I own.  The most popular B was the B-128 and in the end, Commodore managed to sell a measly 15,000 units, mainly in Europe.

Just before Commodore was to plow under the B Series schematics, test machines, and prototype expansion cards, they did what no other computer company had (has?) ever done, hand over these engineering assets to a third party without charge.  The Chicago B128 Users Group (CBUG) became the keeper of all things "B".  CBUG worldwide members bought hundreds of machines from a company called Protecto Enterprises of New York who were liquidating B machines. The CBUG developed or distributed so much software, hardware and hype around the B, that it may have actually been a viable product for Commodore produce.  However its fate was sealed as Commodore moved on to produce almost exclusively home machines like the VIC20 and C64.

In its last and very weak attempt to retain some of the Business segment, Commodore went on to produce a few minor revisions of the original Commodore PET including the 8296, which was supposed to include Paper Clip word processor, Oracle database, CalcResult spreadsheet.  There is some contention about how this software was provided, I believed it was burned on a ROM and inserted into the machine but ICPUG's Joe Griffen informs me that the UK models had similar software simply provided on diskette.  The 8296 that I own (from Britain) definitely does not have any ROM integrated software.

Thus ended the tale of the amazing Commodore PET.

Many Commodore observers believe that three largest factors in Commodores eventual downfall were:

  1. It's all but complete failure to advertise / promote its products at a time when big players like IBM were spending millions

  2. Jack Tramiel's departure in 1984 which caused Commodore to lose its focus

  3. Commodores surrendering of the Business Market to IBM clones when they killed the PET / CBM II lines

My collection of PET's grows every year.  I now have three Chiclet 2001 Pet's, two standard keyboard 2001 PET's, my original 4016 PET, one SuperPET, an 8096, an PET 8296, a C710, and a B128 in the factory box.  I still enjoy playing with them... they are still amazing machines every after all these years.

Commodore PET Chronology and ROM Versions:
Much of the content below was provided courtesy of Joe Giffen of the ICPUG reprinted with permission Feb 21, 2003


- MOS Technologies finishes development of the 6502 processor is bought by Commodore.

1977 January

- Chuck Peddle shows the first PET to Radio Shack, hoping to have them retail it.

- Commodore PET 2001 announced at the West Coast Computer Faire. A complete unit ready to plug in to a mains supply and go. The machine was programmable in BASIC and set the pattern for many machines to come in that it used a non-standard form of ASCII code (often called PETSCII) in which two complete character sets were available. One set comprised upper and lower case letters while the other, the default, had upper case letters and block graphics symbols. This arrangement has carried right through to the 128. The machine also set the pattern to come with outlets being provided for connection of a second cassette drive, IEEE peripherals and non-intelligent peripherals (via a user port). It was available with 4K of user memory and is most easily recognised by its small calculator style keyboard and built-in cassette drive. The Operating System contained a number of errors, most of which were corrected in later versions of the PET. The Operating System of these early PETs is variously described as "OLD ROM", "ORIGINAL ROM" or "BASIC1". These machines power on with the message:


1979 Spring

- The 2001-16 and 2001-32, introduced in 1979, were the outcome of the first and most significant revision of the PET. The memory was at the same time expanded to give options of 16K or 32K. A full size GRAPHICS keyboard was fitted leaving no room for a built-in cassette drive. The Operating System was totally revised, becoming what is know as "NEW ROM", "UPGRADE ROM" or "BASIC2". This removed most of the bugs of "BASIC1". These machines power on with the message:


At the same time the peripherals which had been promised for so long finally arrived. These were the 2000 series printers and the 2040 disk drive (DOS 1).

1979 Fall

- Commodore releases the upgraded PET 2001 series sporting a larger keyboard, expandability to 32k and an improved (bug fixed) BASIC 1.2 which includes disk support.

- The PET was given a new name for sale in Europe, CBM 3000.  This was purely a cosmetic change and the machines are as described above for 2001-16 and -32. The dual disk drive 2040 was also rebranded becoming the 3040 for Europe. The new DOS 1.2 had some, but not all, of the bugs removed.

1980 Summer

- Commodore PET 4000 Series is born in North America. In the summer of 1980 Commodore introduced a new range of machines, with a further revision of the Operating System, containing built-in Disk Commands. This Operating System is known, from its power-on message as "BASIC4". Two principal sizes of memory were available, 16K and 32K.

- Like their predecessors, these machines had 40 column screens and Graphics keyboards. Originally these machines were fitted with 9" screens

1981 Summer

- Following the introduction of the 8032, 12" screens were fixed as standard. These later 4000 series machines are commonly referred to as "FAT-40" machines. These machines power on with the message:


- The peripherals were again upgraded, the disk drive became the 4040, running DOS 2.1 which allowed true relative files. The printers were replaced with the 4022, a unit based on the successful Epson MX-70.  8000 Series. Shortly after the introduction of the BASIC4 machines, COMMODORE released their first 80 column machine (the 8032). The PET had finally come of age!

- This had a 12" screen and a built-in 'beeper'. It was fitted with a standard 32K of memory and the BUSINESS keyboard (often criticized by those who grew up with the 40 column machines). These machines power up, in lower case, with the message:

*** commodore basic 4.0 ***
31743 bytes free

- With the new machine came a further range of peripherals. The 8050, a high density disk drive was introduced with 500K-bytes of storage on a disk and a 132 column printer (the 8023) also appeared.

- Commodore introduces the University of Waterloo engineered SuperPET, a 96k 8000 series PET sporting both a 6502 or 6809 processor. The 6809 mode offers the use of loading in disk based languages and interfacing via a true RS-232 port to larger mini and mainframe computers for programming and language development

- It was around this time that a group of workers at Commodore in Japan are alleged to have put together a computer for their children. The machine was designed to plug into a television set and had colour output. There is a rumor that the machine was given BASIC 2, because those were the chips which were lying around the office. I doubt this, because the operating system is not the same BASIC 2 as in the PET, but is a derivative, having different input/output routines and, of course, the colour features. It may be that the only source code available was BASIC 2! Whatever the truth, that machine went on to become the VIC 20 and set the pattern for a range of cheaper home computers leading to the C44. It was their concentration on the expanding home computer market which led, in my opinion, to Commodore's loss of their lead in the business market.

- In 1981 came the first of a number of variants on the 8032; a machine, known as the 8096, having an additional 64K of memory, not directly accessible from BASIC. A further variant, introduced at the same time, was the SuperPET (CBM 9000) (Micro Main-Frame in Europe) with both 6502 and 6809 processors. This supported a number of other languages, including FORTRAN

1983 - Early

- Commodore announced three new ranges of machines (64, 500 and 700). I attended a 'Commodore Show' hosted by my dealer and my notes reveal that the 500 and 700 machines were not actually on display. At the time I described the machines as follows:

- Commodore 64 - This machine is the cheapest of the new CBM machines. It is an extension of the popular VIC machine and is aimed at the advanced hobbyist.

- Commodore 500 - The 500 series is described by CBM as the "Professional/Scientific" computer. The machine features a 40 column colour display, although as with the 64, no screen is provided with the basic machine.

- Commodore 700 - This series of machine is described by CBM as the "Business" computer. The machines in this range cater for an 80 column monochrome screen, which can either be supplied with the machine, or in the form of a separate monitor. The machine can run most of the software which is available for our 8032/8096 machines, although some of the more advanced techniques (such as screen addressing) may not work without modification. The 700 series will have BASIC as their standard language but will be able to accept PASCAL, FORTH, LOGO and other "soft-loaded" languages. Additionally, both the 500 and 700 series machines can accept a "second processor" option of either a Z-80 or 8088 microprocessor. These will allow the machine to run under either of the "Industry Standard" systems of CP/M-86 or MS-DOS, allowing a vast range of programs to be used.

- Of these machines, the 64 has, of course, been an incredible success; the 500 was still-born and the 700 was re-launched at least twice, before being finally ditched in favour of a revamped version of the 8000 series.

- At the time the 700 was announced, the final floppy disk variant, the double sided 8250 was introduced, giving 1 megabyte of storage on standard 5.25 floppies.

- In Jan '83 the 8000 series was given a facelift by adoption of the Porsche designed casing of the 700. Popular rumour at the time suggested that the suffix "-SK" did in fact stand for "Smoove Kase"!

- Although the new packaging made a few differences to the connections - edge connectors were replaced with IEEE 'D' connectors, the Operating System was the same as on earlier 8000 series machines.

1984 - 1985

- Over the next two years Commodore produced a few more variants of the 8000. The 8296 featured 96K of additional RAM. At the time Tom Cranstoun was reported as saying that 32K of this could only be got at by the user opening the machine and changing the links. The final versions of the 8296 were the 8296D with a built in 8250 drive and the 8296GD with a high resolution graphics board and drive. The operating system was still BASIC 4.

February 1986

- In America, the 700 (or B) series is currently enjoying far greater support than it ever did when it was available. Commodore gave away most of the rights of the Bs to the Chicago B128 Users Group (CBUG) who have taken 'the orphan' to their breast and a truly incredible amount of development work has been carried out by their members.

- A 1M-byte expansion is available and the 8088 Second processor which never appeared for sale has been rescued from the depths of Commodore's research labs and CP/M-86 is now available for the 'B'.

- On the software front, having been given a release by CBM to obtain all material for the 'B', their people have managed to set up some good deals with the software houses. Superoffice is available with Superbase V2! Oh, Precision, how we would love that for the 8096. Precision have also produced Superscript 3 for the 'B'. Version 3 is the menu driven one seen on the 64 and 128.  JCL's 700 workshop was available under licence to CBUG members for about $30, and the Petspeed compiler (my favourite) was available for $99.

- CBUG have also obtained a lot of original Commodore documentation (much of it rescued in the nick of time as Corby was closing) including the 8088 schematics & CP/M-86 info (40pp), software dev't info (302pp) and the original Programmers Reference (798pp).

1986  Commodore abandons the Business market when it dropped the 8296 and ended the 'PET' range

Click HERE to go to our full Commodore PET page

Click HERE to see a small Commodore PET 2001 .jpg

Click HERE to see a small Commodore PET 2001 keyboard closeup .jpg

Click HERE to see a small .jpg of the Commodore Product Line Up in 1982


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