[Simh] What is the file VAX/vmb.exe for?

[Thomas Pfau]

Peter Lund wrote:
> I noticed that simhv37-2.zip contains the file VAX/vmb.exe which wasn't
> there in simhv36-0.zip (or thereabouts).
>
> I can tell that it has something to do with booting due to it being
> mentioned in the cpu_boot() function in VAX/vax780_sbi.c.  By googling
> for it I found it mentioned in relation to some OpenVMS booting stuff
> but that's pretty much all I know.

The 11/780 had a small LSI-11 that performed console functions.  During
the  bootstrap process, the LSI would load VMB.EXE into the 11/780's
memory, load registers with values telling it what to do and the start the
VAX processor executing this program.  VMB.EXE would then start the
bootstrap process.

With SIMH, there is no LSI-11 so SIMH itself needs to get VMB.EXE into the
VAX memory to start the bootstrap process.

> What is the relation between that and ka655x.bin?

VMB.EXE is a VAX program.  KA655X.BIN is microcode.

-- 
tom_p
http://nbpfaus.net/