[Simh] Booting a pdp from console

[dave porter]

Ron Hudson asked:

>Using a real PDP11, I suppose one would examine an address 
>and then start execution to boot from a hard drive? The address
> being that of some fat fingered  in boot loader?
>(no BIOS rom eh?)

It depended on the model.  The older/smaller/cheaper models
had no ROM, so you had to key in a loader.  ROMs were available
as an option on those, some of them diode matrixes that could
be custom-programmed with wire cutters (!).

Later/larger configurations used to come with standard ROMs,
where you'd set on the keys a particular start address and/or
a device number.

Laler still, PDP11s came with microcoded consoles that
spoke to a console terminal instead of having proper keys
and lights.