Andrew, a friend from the ARC Group, has supplied me with a lot of funky gear including a box of S-100 cards, a couple of chassis, several 8″ floppy disk drives, and about 500 8″ floppy disks.
I never imagined that i would get an opportunity to work with S-100 bus. Components are difficult to find and, when they do appear, people expect an arm and a leg for them.
I had no idea if any of the cards were related to a particular system so all i could do was catalogue them and see if any patterns emerged. One pattern did emerge – there were several Cromemco cards including:
- a Single Card Computer (SCC)
- a 64KZ Dynamic Memory Card
- a DPU Dual Processor Card with Z80 and 68000
- a MCU Memory Control Unit
- a 512MSU Memory Storage Unit connected to MCU via a MBus ribbon cable.
- a 16FDC Floppy Drive Controller
- a TUART Twin UART
Not knowing much about Cromemco, i started reading and a new world opened up. The Cromemco community seems to exist primarily as a Google Group with a huge repository on GIT. This proved critical because i did not have a skerrick of software or doco. There was nothing related on any of the 8″ disks that i had.
The repository includes a vast array of manuals, disk images, software etc.
I realised that there were sufficient cards to be able to build a system capable of running Cromix (a Unix look alike). It would consist of:
- a DPU Dual Processor Card with Z80 and 68000
- a MCU Memory Control Unit
- a 512MSU Memory Storage Unit connected to MCU via a MBus ribbon cable.
- a 16FDC Floppy Drive Controller
- a TUART Twin UART (optional)
I’m not sure where these cards came from. Perhaps they had been used in a bespoke design or stripped out of a Cromemco system. If the latter, then the chassis and drives have not made it into my hands. I will need to use a third party chassis, drive enclosure, and drives. Also, notably missing from the list, is a hard disk controller such as the Cromemco WDI-II but i did see that it was possible to run a skeleton Cromix system from floppy disks. That would be good enough for me (until it wasn’t).
It was also possible to build a system capable of running Cromemco DOS (a CP/M look alike) and that seemed like a less intimidating option to start with. It would consist of the following:
- a DPU Dual Processor Card with Z80 and 68000
- a 64KZ Dynamic Memory Card or an MCU Memory Control Unit and a 512MSU Memory Storage Unit connected to MCU via a MBus ribbon cable.
- a 16FDC Floppy Drive Controller
And there was an even simpler machine that could be built using just the SCC.
I started with the SCC and then used it to help locate faults in other boards. Then i moved onto the CDOS system which was also handy for finding faults in the 68000 system.
