Chuck Guzis wrote:
ISTR reading a (red) hardcover book that dealt with
custom
microprogramming both the S/360 and the Spectra 70. From what
I remember, the 360/30 was the system of choice for "hobby
microprogrammers" with the Spectrola a close second.
_Microprogramming: Principles and Practice_, Samir S. Husson, Prentice
Hall, 1970