On Wed, May 30, 2018, 20:26 Jon Elson via cctalk <cctalk@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.
