Research on Rent's rule in electrical engineering, the applied sciences, and technology has been based on the publication of a 1971 interpretation of Rent's memoranda by B. S. Landman and R. L. Russo. Because of the wide impact of Rent's work and requests from researchers, we present his original memoranda in this paper. We review the impact of Rent's work and present the memoranda in the context of IBM computer hardware development since the 1950s. Furthermore, because computer hardware components have changed significantly since the memoranda were written in 1960, a new interpretation is needed for today's ultra-large-scale integrated circuitry. On the basis of our analysis of the memoranda, one of the authors' personal knowledge of the 1401 and 1410 computers, and our experience in the design of high-performance circuitry for microprocessor chips, we have derived an historically equivalent interpretation of Rent's memoranda that is suitable for today's computer components. We describe an application of our historically equivalent interpretation to the problem of assessing on-chip interconnection requirements of control logic circuitry in the IBM POWER4e microprocessor.