[vcf-midatlantic] 8-bit ISA slot Single Board Computer
hjohnson at retrotechnology.info
Tue Sep 20 14:00:37 EDT 2016
Joseph Oprysko posted:
> Is anyone here aware of such a beast? I have a Heathkit/Zenith Z-150
> system. It's motherboard is literally just an 8-Bit ISA backplane, the
> computer occupies 4 of the ISA slots.
I have Z-150 and related documentation. Zenith/Heath produced a number
of models of ISA computers which used passive backplanes and several ISA
boards to complete the PC-nearly-compatible computer. Other Zenith
products used IBM-type motherboards with most of the PC functions on
> I'm curious if there exists a Single Board Computer that would work in the
> 8-bit slots.
> What I would actually like to try is to have multiple SBC's on the ISA bus,
> and have them communicate with each other.
There may be single-board PC's which fit a single 8-bit ISA slot. But
many were 16-bit ISA, the longer slot. And the PC-104 stackable bus
standard, is essentially the ISA bus on a different connector. YOu can
look up PC-104 if that's not familiar.
Running multiple ISA-bus "masters" on one ISA bus, may be a problem.
Briefly: they each expect to drive the bus as a single master. There may
be products that can share the bus with each other.
(shrug) you'll have to do some homework to become familiar with such
things; and then of course find now-vintage products which will share
the bus; and of course determine how to set them up, boot up sequences,
who is in charge when, and so on.
Likely more common, are slave CPU boards, where a task or a user gets a
CPU on a board with memory and I/O; but uses the bus to share resources
like hard drives. this was common in S-100 TurboDOS systems. Some of the
S-100 "IEEE-696" CPU boards, can release the bus to another CPU or DMA
bus-master; some of those boards are fairly functional "computers".
Multibus did this too.
But I'm guessing the idea, is to use IBM-PC ISA-class products, to check
out multiple bus-masters and multiple CPU's, in a vintage way. a
modified ISA backplane, may be such a way. A custom backplane may be
able to adapt ISA "no share" bus masters to access common ISA bus
devices. But you might look at PC-104; they are smaller cards, more
integrated and so with more features; and they may have a multi-master
standard as part of PC-104. And of course, they are vintage now. ;)
Herbert R. Johnson, New Jersey USA
http://www.retrotechnology.com OR .net
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