Wanted: Just about anything IMSAI

From: Michael Hart <dragon_at_panix.com>
Date: Sat Feb 6 00:03:23 1999

>> Three questions:
>>
>> Where will you be shipping from?
>>
>I'm in Denver
I am in New Jersey.

>> How much do you want?
>>
>I'd settle for a similar function for the ISA bus.
I don't have any ISA cards to give away, so I offer you $10 per card.

>What's a slave card?
A Slave S-100 card usually have some memory, a CPU and at least a RS-232
connector. What would happend is that when your system started up. Your
master CPU on the S-100 bus would load the memory of the slave cards with
something, like the slaves own version of CP/M. You could have as many of
these things as you box could fit. There were a number of way I/O to the the
users of the system could be accumplished. One was route all the slaves I/O
to the user throught the the s-100 bus to a I/O card connected to the users
terminal. The other and more tipical way what to have each user have their
termianl connected to the slaves RS-232 port. The drawback to this method
was there had to be a bus master handling all bus traffic to an from I/O
devices such as disk drives for each of these slaves since the slaves could
not do it themselves.

Compupro made a Z80 slave card that supported between 64K and 256K or RAM
that had a RS-232 port. If I recall correctly you could only put 8 of these
on you bus. But you could hack them to put as many as your bus supported.
This is the type of board I am looking for.

There was another method of placing multiple CPU on your bus. That basical
ment building a Single Board Computer (SBC) that could use the S-100
Temporary Master Access (TMA) hand shaking. The S-100 supported up to 16 of
these TMA on a bus. The advantages is the TMA's tended to use the bus more
efficiently comparied to slaves boards with requried a bus master present
servicing them. I don't know who use to make SBC that fully IEEE 696
standard for TMA access but do know that they were out there.



>I have a couple of primitive (as primitive as any S-100 board) SBC's from
>whoever made the famous SBC-100 and SBC-200. I have one of each, I think,
>and they're in unknown condition, as I inherited them from someone who was
>moving away and didn't want to haul them.

What an SBC-100 and a SBC-200 do?

Keep me in mind should you know of anyone who has IMSAI 8080 system for sale
out in your neck of the woods.

Michael
Received on Sat Feb 06 1999 - 00:03:23 GMT