[Simh] Tell me about console terminals and related things

[Vorländer, Martin]

> So as I delve into VMS and related concepts, I’ve come across mention of
> console terminals and “operator’s consoles.”
> I gather that SIMH simulates one of these when the machine starts up, but
> I’m a bit less clear on how this compares to the real hardware.
> When the VAX boots, it obviously has a prompt for boot options and such.
> Would this be displayed on, say, a VT100 somewhere?

Every(?) VAX has a special serial port (on some Q-BUS VAXen I've seen it's located
directly on the CPU board). This is the operator's console, the serial line the VAX'
BIOS communicates with. Under VMS the device is called OPA0.

The situation can be a bit different if the VAX has a graphics card built in (i.e. is a
"workstation" class VAX). On those there's a DIP switch that controls where the
BIOS output is directed to - the special serial line or the graphics card.

cu,
Martin