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Re: Mystery hardware query



David Empson wrote:

At its peak, our network included about 17 Apple IIe workstations on the
Nestar network.

Just out of curiosity, what data bandwidth did the network support?

It was an 8-bit parallel bus, with handshaking. Somewhat like a parallel
printer interface, with a data strobe and an acknowledge. I don't recall
details about the protocol and I'm not sure if I ever analysed its
performance in close detail.

Each sector or block was transferred over the network as a single burst,
and the average performance of the network was pretty bad with a lot of
computers tring to use it at once, probably due to the contention phase
and polling time.

Some specialised applications were able to hog the network for short
periods in order to transfer a larger amount of data. One example was
the network login screen, which loaded a fairly large amount of data
quickly.

What you describe sounds very much like the original Corvus "flat cable" network. It was wired in a star configuration with each computer having a 34-pin ribbon cable back to a device called a multiplexer. This connected to a hard disk and acted as an arbitrator. I have a bunch of Corvus hardware and software (probably just about everything they ever made), but haven't had it setup for a while.

The flat-cable networks were replaced in 1982 or thereabouts with the twisted-pair OmniNet, which was a daisy-chain topology using a form of collision-detect / backoff protocol.

Steve