Personal Computer Museum, Canada's Videogame Museum

Commodore SuperPET - Additional Info

Commodore SuperPET

Speed1 MHz
Memory96 KB
Release Date: 1/1/1981
Original Retail Price: $2,995.00
Donated By: John Bos
About the SuperPet – John Bos

The Commodore PET uses the 6502 microprocessor. By adding an additional circuit board with extra memory on it and the 6809 Motorola processor complete with software developed by Watcom a new model computer was created called the SuperPet.

By flipping a switch to the 6502 position the computer was fully compatible with the original Pet and would run Commodore BASIC in 80 column mode.

By flipping the switch to the 6809 position the computer could be loaded with the software from the Waterloo University :

  • microBASIC
  • microFORTRAN
  • microPascal
  • microAPL
  • microCOBOL
  • microAssembler
This two board SuperPET was a bit later replaced by an one board model with the same functionality.

A company in the US called Microware had developed a highly portable multitasking operating system for the 6809 processor called OS9. It did not only everything that you expected from an UNIX system, but it had additional features. For instance running programs are given at start up a priority number between 1 and 255. All the running programs were given a time slice of 200 milliseconds. After completion of the run the priority numbers of the waiting programs were decremented by one. Once the priority number became 0, that program would from then on join the running programs and also get a time slice.

The program modules consist of a Header section with all the information for the program followed by the program itself and/or any data.. The beauty of this setup is that if a module had to be changed you could make a new version of that module and store that in the working space. You could enable that new module and disable or delete the old module on the fly. No need to reboot the computer.

To make it possible to run OS9 on the SuperPET, Avy Moise and Gerald Gold of the York University in Toronto developed an add-on board. This OS9 board was installed in Toronto on several one- board SuperPETs and on one two board (older model) SuperPET, which happened to be my SuperPet, and I installed it myself.

Many kits were shipped out and sold all over North America and most of them worked very well on the single board SuperPET. I also heard that any problems were mostly with the older two board SuperPETs.

The SuperPET in Syd's museum is unique in so far that it was the first SuperPET converted in Toronto that worked. Also the first one in Ontario and also in Canada and of course in North America. Not only that but also the very first one in the whole world here on Earth. It also has an added speaker and a reset button.

In space NASA also used OS9 on the ill-fated Challenger. Several programs were available for OS9 or you could make and run your own. AFAIR Radio Shack did also market a computer that did run a slightly smaller version of OS9 as that of the SuperPet.

When Motorola introduced the 68000 processor, Microware brought out a version of OS9 for it.


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This computer is currently interactive in the Museum.

CBM 8050 Drive

CBM 8050 Drive
Release Date: 5/1/1980
Original Retail Price: $1,695.00
The CBM 8050 is an exceptional drive, able to hold 512k on each DS/DD floppy - a total of 1 MB combined.

CPU: MOS 6502

RAM: 2k

DRIVES: 2 x DSDD 5.25 Floppy Drives (GCR)

I/O: 1 x IEEE-488 Interface


This peripheral is currently interactive in the Museum.

Commodore SFD-1001 Disk Drive

Commodore SFD-1001 Disk Drive
The SFD 1001 is a single-drive, low profile version of the better known 8250 IEEE-488 disk drive capable of storing 1 MB per floppy disk, powered by CBM DOS 2.7. The SFD is powered by two CPUs, one for the floppy drive controller and the other for file handling and bus transfer. The SFD, as well as the 8050 and 8250 disk drives, have twin 6502s.

User Comments
John Seither on Sunday, October 20, 2013
I've had my SuperPET since it was delivered to me in about 1983 while stationed in Honolulu with NCIS. The initial shipment from the mainland came filled with rocks. It's been in its original box, alone with the accompanying boxed 8250 disk drive, for well over a decade. I sometimes toy with starting it up again; it worked fine when originally stored away about a quarter century ago.
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