CompuServe Messages

"It also depends on whether the addon devices are buffered… if the devices are made well there shouldn't be a problem." Sorry, it's not that simple. If you hang multiple unbuffered devices on the bus, you court failure because of 1) transmission line effects and distributed capacitance from the longer unterminated bus lines, and 2) decreased noise margins from increased loading. (The bus is for the most part hanging directly off the CPU pins. Take a look at a 680×0 spec sheet sometime to see how little capacitance and loading it can tolerate.) If you hang multiple buffered devices on the bus, you court failure because of increased propagation delays from one end of the chain to the other. Theoretically it should be safe to hang a buffered device on the bus and then hang an UNbuffered device or two on the other end. But then you're approaching the card cage concept, which is one of the two approved methods for Amiga expansion. Buffered or unbuffered, well designed or not, the simple fact is that the bus is only designed to handle ONE device, be it a SOTS box or a rack. If it's a SOTS box, adding a second device may or may not work, and there are effectively no guarantees. If it's a rack, designed to spec, then you should be able to load up the rack with to-spec cards with no problems. Just didn't want you to think that if you bought device A and device B, both buffered, that you were automatically safe… it's still a gamble. Rick