Ideas for a simple, but somewhat extendable computer bus

Chuck Guzis cclist at
Mon Nov 20 14:20:10 CST 2017

On 11/20/2017 11:37 AM, allison via cctalk wrote:

> I did that back when with a S100 machine expanded with multiple 
> Z80s(local ram and MMU), global mmemory and  8085s and 8749s to have
> intelligent peripherals and shared loading and tasks.  An interesting
> experiment and some elements still are in operation.   However 
> software development of the day (1980) was primitive and some
> concepts were only experimental.  Networking was one of the things
> most productive and lead to many hardware simplifications.  It proved
> that while CP/M was a good single thread development environment it
> had limits that only a new OS could overcome.  The most significant
> was resource management (memory, storage, and IO) followed by task 
> and process management.

I did a similar thing, ca 1985-6 with a bunch of commodity PCSs in a
fault-tolerant setup and used a simple machine-to-machine full-duplex
serial connection, using shift registers and short twisted-pair
differential connections.  Uncomplicated protocol and simple to
implement.   I'd have to go back to my old documents and see what the
link speed was, but IIRC, it was pretty fast, in the megabit/second
range.  The limiting factor was the ISA bus it was hooked to.


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