ISA expansion boards/cases

The backplanes having more than 8 ISA slots tended to work badly, as a function of how full and how long they were. Notable exceptions are/were the 12-slot passive backplanes sold by at least one manufacturer, which managed to operate quite well. The key is that these were not on a motherboard and thereby allowed, among other things, placement of the main CPU close to the center of the backplane while the remaining cards were installed working inward from the ends. These things have always been ridiculously expensive due to the low volumes in which they're produced. There were a few expansion boxes built with a cable having a bus interface at each end, capable of converting the differential signals on the cable betwen them back to single-ended TTL levels. These didn't ever work particularly well, i.e. were very fussy about what was in the expansion chassis, as the bus timing was altered by the cable delays. I wouldn't expect such an item to be low-priced, though, just because of its relative rarity. Dick -----Original Message----- From: Adam Fritzler <mid(a)auk.cx> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, October 09, 1999 12:07 PM Subject: ISA expansion boards/cases