I am in New Jersey. I don't have any ISA cards to give away, so I offer you $10 per 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. 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