Although most of the components are no longer manufactured there seems to be plenty of 'old new stock' available through the various marketplaces online.

The system design philosophy was to create a eurocard based system with DIN41612 connectors which was very popular in the 1980 in Europe to create 8-bit systems. Commercial systems at the time where Gespac, EuroCUBE Celeste and Eurocom. The Elektor magazine also published an Eurocard system running FLEX. There were also many systems developed by hobbyists and I have taken inspiration from the nice UniFLEX system developed by Kees Schoenmakers (https://github.com/kees1948/UniFLEX).

I focused on using only 5V logic but avoided the usual forest of TTL logic and PAL/GAL solution for the glue logic. Instead I used 5V CPLD devices which are fast, cheap and can hold a lot of logic allowing to add some nice features to the system such as fast memory to memory DMA but also esoteric ones like a hardware CRC calculation of OS9 modules. With in-circuit (re)programming system development & testing is quick without having to remove devices from the PCB.

Source code for both UniFLEX and OS9 level II is now available, something we could only dream about having in the 1980s since both hardware and software were rather expensive. Full details will be made available through my Codeberg GIT.

The system closely matches the CMS9639 from the 1980s which was similar to the GIMIX III board. Thanks to the SARDIS technology website (https://sardis-technologies.com/oth6809/cms.htm) there is a lot of information on these nice systems.

The addition of a dedicated ethernet interface offers opportunities not available in the 1980s.