On 05/24/2016 11:39 AM, Eric Smith wrote: > On Tue, May 24, 2016 at 12:25 PM, Paul Koning > <paulkon...@comcast.net> wrote: >>> On May 24, 2016, at 2:07 PM, Chuck Guzis <ccl...@sydex.com> >>> wrote: ...and the "transformer" ROS used on the 360/40 (and >>> others). >> You mean "Core rope memory"? > > IBM's TROS and Core Rope Memory use the same principle, but the > physical construction is significantly different. Core rope memory > was very labor-intensive to manufacture, while TROS was not.
There's a photo here; http://www.cs.sun.ac.za/museum/memory.html I seem to recall that reworking the 360/30 microprogramming was preferred by tinkerers over the 360/40 was primarily that CROS was easier to work with than TROS. I don't recall what the RCA Spectrolas used. --Chuck
