[Coco] Some MM/1 system board pics..

[Francis Swygert]

The MM/1 was a decent computer, but had many problems also. For one it was designed "by committee" and took forever to get out to market. By the time it came out many would be purchasers had moved on. It was done that way to get as much community input as possible so it would have a better chance of being what more people wanted, but to many cooks can spoil the pot. 

It was also intended to be affordable, so a CPU with some integrated features was used. It was based on a slower 68K core, and though the integrated features (I forget the exact ones) made the motherboard a little less complicated and reduced costs a bit, it also made it impossible to upgrade the CPU later. A standard low cost 68K CPU that could be upgraded with a faster one later would have been a better cost saving feature (IMO), but probably wouldn't have saved that much. It was designed to use a few CoCo peripherals, like the joysticks and monitor. IIRC that's about all it could use though. The monitor was a cost savings, but then you were relegated to running only one of the computers -- MM/1 or CoCo3. The cost of the OS (OS-9 68K) was an issue also. 

None of the computers hoped to replace the CoCo could run CoCo software, they were all OS-9 based. An emulator was hoped for, but never materialized, and would have been slow. Frank Hogg Labs made the TC-9 which was a backplane design that used a 6809 card. It was somewhat compatible with CoCo OS-9 software (some patches were needed for most), and had a 68K card that could be purchased later. It was more versatile, but also more expensive (than the MM/1). Until the FPGA CoCo came out there was just no hardware to replace a CoCo. It's a few years too late to make much impact.
  Frank Swygert
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