Positron 9000 -- 6809 Computer

photo of Positron 9000 computer

(This page is still under construction.)

The Positron 9000 computer ..... in England.

Positron 9000 features:

The October 1982 issue of Personal Computer World (PCW) magazine published a lengthy review of the Positron 9000. It sounds like only OS-9 Level I was available at the time of this review, but the machine was designed especially to run Level II.

Looking at these pictures and ROM dumps, I counted approx. 184 ICs on the huge main PCB and another 90 on the large keyboard PCB. That totals 274 ICs! It must have been very expensive to manufacture this computer.

It uses from 1 to 8 of the Motorola MC6829 Memory Management Unit (MMU) chips, which Motorola never put into volume production. The MC6829 app note makes for some interesting reading.

Thank you to Mike Miller who pointed me to information on this very rare computer.

Søren Roug has posted the source code for modules OS9p1, OS9p2, and IOMan for OS-9 Level 2 V1.2 for the Positron 9000. He also has an HTML version of the PCW review.

More information:
story of how Peter Plinston got the grant money to start Positron Computers
photograph of Peter Plinston
Facebook page of the Binary Dinosaurs museum where Adrian Graham is restoring a Positron 9000
text of Computer Weekly announcement of new distribution channel for the Positron 9000
eBay listing
forum messages
restoration blog
price shown as £2134, also mention of Positron 900
 Also mentioned on page 131 in the book "6809 Machine Code Programming" by David Barrow
Viewdata and Prestel, types of videotex in the UK (similar ideas as Telidon in Canada)


"OS-9" is a registered trademark of Microware LP.

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Last revised 2022-Jun-01 12:30 PDT.
Copyright 2021-2022 David C. Wiens.


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