> On Nov 9, 2015, at 12:26 PM, Eric Smith <space...@gmail.com> wrote: > > On Thu, Nov 5, 2015 at 8:18 PM, Guy Sotomayor <g...@shiresoft.com> wrote: >> * The expansion bus in the IBM PC was the same bus as the System/23. The >> connector was rotated 180* so that some of the less expensive >> cards from the PC couldn't be used in the System/23. The other >> reason for this was since the IBM PC was done on a "shoe string" >> budget, they could take the System/23 cards and only had to do some >> minimal re-layout of the board. > > Did the System/23 also use edge-triggered interrupts, rather than level?
Yes. > > Do you have any idea why it was thought a good idea to use > edge-triggered interrupts? I wasn’t really involved in the HW side of things but I think it was because it was “easier”. I think at least one device just generated a pulse for an interrupt rather than having some sort of latch. TTFN - Guy