TRS-80 Fragmentation

Fred Cisin cisin at
Thu Apr 26 19:50:08 CDT 2018

>> I believe the Z-80 was subordinate to the M68K.

On Fri, 27 Apr 2018, Eric Smith via cctalk wrote:
> In high-level conceptual term, maybe, depending on the software.
> In term of the actual capabilities of the hardware, the Z80 was firmly in
> control of _everything_ in the machine, including control over the MC68000,
> while the MC68000 had no direct control over anything but its MMU (built
> from TTL) and memory. If code running on the MC68000 wants to talk to
> anything at all, disk, tape, console, printer, serial ports, etc., all it
> can do is politely request that of the Z80. In that sense it's like the CPU
> of a CDC 6600, which can't do anything without the PPUs

So, the Z80 ran CP/M and TRS-DOS, functioning as in I/O coprocessor for 
the 68000, . . .

As in small business, which is "subordinate",
engineering or administration?

A friend of a friend was very proud of his Z80/68000 Cromemco.  He was a 
little offended when I compared it to the Radio Shack Model 16.

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