Rent’s Rule
In 1960, E.F.Rent published two IBM internal memoranda containing log plots of the “number of pins” vs the “number of circuits” in a logic design, which yielded:
Where Np =no. of external signal connections on a block, Ng= no. of logic gates in a block, Kp is a proportionality constant, and ? is Rent’s Constant.
For IBM computers at that time, Kp = 2.5 and ? = 0.6
Later used to determine the average interconnect length in a gate-array as a function of the number of gates and the row spacing.