Ideas for a simple, but somewhat extendable computer bus
allisonportable at gmail.com
Mon Nov 20 13:37:41 CST 2017
On 11/20/2017 01:18 PM, Chuck Guzis via cctalk wrote:
> On 11/20/2017 05:40 AM, allison via cctalk wrote:
>> Creating a bus to accommodate any one cpu at a time is far more
>> straightforward and there are plenty of
>> examples than one that is running a mix of many cpus.
> Oddly enough, I'm in agreement. :)
> Today, it really makes little sense to have memory, CPU and high-speed
> peripherals on separate bus slots. At least for the cases being
> discussed, memory is dense and inexpensive enough that there's really no
> good reason to put it somewhere else.
A good example would be a matrix of SBCs (with local memory, IO as
communicate via common bus be it parallel or serial. The key then is
and arbitration. A protocol to hand packet communication is easy and
a request/grant master slave from the current bus master , token bus, or
CSMA/CD are all possible.
> Data transfer between peripheral devices and CPUs is a different matter
> and can be handled by existing serial buses--which is what I thought the
> original question was.
Likely true but IO can be local to a CPU or several and handled for
Of course then the concept moves to system space where the SBC are
programming is more complex in organization. Likely more fun rather
out hardware. Then again I'd find that part fun as well.
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
and tasks. An interesting experiment and some elements still are in
software development of the day (1980) was primitive and some concepts
experimental. Networking was one of the things most productive and lead
hardware simplifications. It proved that while CP/M was a good single
development environment it had limits that only a new OS could
overcome. The most
significant was resource management (memory, storage, and IO) followed
and process management.
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