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Old 28th Apr 2019, 8:43 pm   #1
john_newcombe
Hexode
 
Join Date: Apr 2019
Location: Skipton, North Yorkshire, UK.
Posts: 252
Default Gemini 80-Bus System

I recently purchased a Gemini system and I was wondering if there is anyone out there who has an interest in these machines

The unit came with much documentation and no software or keyboard. However, I successfully knocked up a PS/2 to parallel ASCII keyboard adapter using an Arduino Micro and have been able to create a cassette archive of the CP/M version of MBasic (MBASIC.COM). This runs directly on the RP/M monitor in the machine. However, I am hoping to boot to CP/M from a floppy (or GoTek). After contacting a member of this forum I have kindly been given some raw disk images to work as well as a pointer to the Xbeaver 80-Bus emulator.

There were a couple of interesting details regarding the machine I have. The first is that it includes RP/M version 2.2. This is odd as version 2.2 of RP/M was (supposedly) never released, the version numbers leapt from V2.1 to V2.3 to avoid confusion with version 2.2 of CP/M, this was confirmed in an article written for 80-bus news by RP/Ms creator Richard Beal (80-BUS vol. 3 iss. 6 p. 9).

The second interesting thing is that there is also an EPROM containing the Gemini Boot ROM for 8 inch Disks. This appears to be written by Roger Brooks, and, based on the included source code listings and manuscript amendments, this would appear be the machine he created it on.
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