31 May
2018
31 May
'18
8:28 a.m.
On Wed, May 30, 2018, 20:26 Jon Elson via cctalk <cctalk at classiccmp.org>
wrote:
The early 780 had most microcode in ROM, and had a
small
writable control store for special OS-required options and
patches. Later machines had more WCS, but I think they
still had some non-writable control store.
The control stores of the 11/785, 8600, and 8650 were entirely WCS.
Probably the so-rare-as-to-be-almost-nonexistent 9000 series had entirely
WCS as well.
All other VAXen had (relatively) large ROM control store and tiny WCS or
patch store.