gwyn@brl-smoke.ARPA (Doug Gwyn ) (07/12/87)
In article <1807@megaron.arizona.edu> gmt@arizona.edu (Gregg Townsend) writes: >.... I assume this was just conceptual >and actually involved negative logic instead of extra gates. Correct; since CDC used a form of (unsaturated) RTL, each gate acted as an inverter modified by a second signal (the gate signal). Their circuit diagrams were pretty cute: squares and circles alternated as the signal switched from positive to negative logic on its path through the transistors. The reason for this architecture was speed via both fast (unsaturated) switching logic and minimal gate count (therefore no extra inverters just to make the logic diagrams more intelligible). After one got used to it, it all made perfect sense.