Key points are not available for this paper at this time.
A PDP-1 computer was donated (by the Digital Equipment Corporation) to the Electrical Engineering Department of the Massachusetts Institute of Technology in late 1961. In May, 1963 the first time-sharing system was operational. Since 1963 this PDP-1 has undergone substantial modifications (c.f. Appendix). Presently the machine has twelve thousand words (18-bit) of five microsecond memory arranged in pages of four thousand words. One of these pages is reserved for the system code and is protected from user references.
Ackerman et al. (Sun,) studied this question.