Uploaded December 2024 | Updated September 2026, 3 weeks ago
I wanted a second vintage computer that runs the ISIS-II operating system, so I set out to turn an 80/24A multibus CPU board into a Series II Development system. The Series two has a pair of boards, the IPB/IPC CPU board and the IOB/IOC IO Controller board. The Series II was inherently a multi-processor system, with one main processor (either an 8080 or 8085) together with a secondary 8080 processor on the IOC. The IOC handled the terminal and disk duties on behalf of the system. I had an 80/24A to serve as the primary process, but I don't have an IOC to handle the disk, and to run ISIS you really need a disk. So I built my own, using a Raspberry Pi to serve as the disk controller. This allows me to serve disk images directly from the raspberry pi. I'll add a real floppy drive in the next video. I also demonstrate using the 80/24A board by itself, running BASIC and FORTH. For more vintage computer projects, see smbaker.com
I wanted a second vintage computer that runs the ISIS-II operating system, so I set out to turn an 80/24A multibus CPU board into a Series II Development system. The Series two has a pair of boards, the IPB/IPC CPU board and the IOB/IOC IO Controller board. The Series II was inherently a multi-processor system, with one main processor (either an 8080 or 8085) together with a secondary 8080 processor on the IOC. The IOC handled the terminal and disk duties on behalf of the system. I had an 80/24A to serve as the primary process, but I don't have an IOC to handle the disk, and to run ISIS you really need a disk. So I built my own, using a Raspberry Pi to serve as the disk controller. This allows me to serve disk images directly from the raspberry pi. I'll add a real floppy drive in the next video. I also demonstrate using the 80/24A board by itself, running BASIC and FORTH. For more vintage computer projects, see smbaker.com
