That's kind of neat. Did he just extend the bus in a "raw" fashion or put buffers on it? (The downside of the 5161 was any memory device in the 5161 had an extra wait state thanks to the speed of the buffers, which were necessary to deal with the capacitance on the cable to the expansion unit.)
They were buffered, from my poor memory. So was slower when you exceeded mainboard memory, but you could load entire tapes into memory, which let you do things no one else could. Faster processing than disk/tape access.
