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Positron Computers Ltd
Peter Plinston was sponsored by Pilkington Glass in 1982 after he approached a local New Business Venture with a single board computer based around the Motorola 6809 CPU. With the sponsorship he started Positron Computers Ltd and opened an office in Newton-Le-Willows near Manchester UK.
The history ends there currently, all that I know is this machine was the result - a 6809 powered multi-user viewdata compatible machine capable of supporting 24 users when fully loaded. It's believed to be the only example of a Motorola multi-user reference design that used all Motorola parts. It runs OS9, a unix-like OS that provides each user their own space but with shared executables, so if multiple users were running BASIC9 there'd be one copy of the executable in RAM and each user would have their own reserved memory to use. When the last user exited the executable would be removed from RAM. What's different with this machine is the entire OS is on 5 2764 ROMs, so the external floppies and 5MB hard drive were for userspace programs. The storage hooked up via the IEEE port on the back of the machine.
This one was found in a shed clearance by Steve who I bought it from, so unfortunately he didn't know any history of this machine itself. It's interesting to see it has no identification, serial number or FCCID. It's also quite rusty so the shed obviously wasn't waterproof, fortunately the rust is on the case and a small part of the board at the back.
I've contacted Peter on Linkedin but no response as yet, so if you know anything at all about these machines please let me know!
OS9 ROM images, 5x Fuji MBM2764.
Positron 9000 PCW Benchtest review, page 1, 2, 3, 4, 5, 6, 7

All images and text © Adrian Graham 1999-2021 unless otherwise noted using words. Also on