On Tue, Apr 4, 2017 at 8:35 PM, Paul Koning <paulkon...@comcast.net> wrote: > >> On Apr 4, 2017, at 8:21 PM, Charles Dickman via cctalk >> <cctalk@classiccmp.org> wrote: >> >> ... >> In the course of research, I saw that there was an option to replace >> the braided core ROM that was standard, ... > > Charles, > > I've been studying core ROM for a while now, and there doesn't seem to be a > whole lot of information. One interesting tidbit is that it appears -- but > it's hard to confirm completely -- that it was invented by Ken Olsen (while > at MIT Lincoln Labs). > > Do you have pointers to the PDP-14 rope memory documentation?
http://www.bitsavers.org/pdf/dec/pdp14/DEC-14-HGZB-D_PDP-14_Maint_Man_1972.pdf Forgive me if I have used "braided core ROM" incorrectly, but how I understand the PDP-14 ROM, it was a network of wires threaded (braided) through ferrite pulse transformer cores in a way such that it was possible to address and read data. The current sources and sense amplifiers were similar to that used with core memory. >From what I can gather, never having seen one, the cores in the PDP-14 were actually quite large and fragile. There is information in the field service handbook (Bitsavers) that indicates that a ROM could be destroyed when the board was pulled from the chassis and there was a manufacturer change made to prevent the problem. -chuck