2 Jun
2018
2 Jun
'18
3:35 a.m.
On Fri, Jun 1, 2018 at 6:08 PM, Robert Armstrong via cctalk
<cctalk at classiccmp.org> wrote:
Indeed. I think others mentioned that processor too.. For some reason the
control store was built from 16K DRAMs, and the CPU has to wait while
they are refreshed every few milliseconds.
Eric Smith
<spacewar at gmail.com> wrote:
The control stores of the 11/785, 8600, and 8650
were entirely WCS.
All other VAXen had (relatively) large ROM control store and tiny WCS or
patch store.
You forgot the 11/730 and 725. The KA730 used 2901 bit slicers and the
control store was entirely in RAM. After power on it was a paperweight until the 8085 CFE loaded the microcode.
Loaded from a TU58 cartridge, which is the main reason my 11/730 is not
running at the moment. The hardware is fine, I've rebuilt the drive rollers,
but as yet don't have a readable tape (not even blank, to write the
microcode onto).
Incidentally, did DEC ever release any details (flowcharts, source listings,
etc) of the 11/730 microcode? And what about the control PROMs for the
memory system. The technical manual implies there was a listing of those,
but I've never found it.
-tony