5 Sep
2023
5 Sep
'23
11:03 p.m.
On 9/4/23, Clem Cole <clemc(a)ccc.com> wrote:
Even with the VAX, the front-end runs on an LSI-11 with floppies, so things
like microcode were loaded into the VAX and stored in ROM.
I think you meant either "stored in RAM" or "not stored in ROM". The
LSI-11 front end for the VAX-11/780 (and other early VAXen?) was
connected to the SBI (Synchronous Backplane Interconnect--the system
bus) and performed three main functions: microcode load and system
bootstrap initiation, interface for the system console (originally a
LA-36 dot matrix terminal), and some system diagnostics. CPU
microcode was stored on a 5" floppy disk connected to the LSI-11 and
was loaded into RAM at system power-up.
-Paul W.