[Simh] Tell me about console terminals and related things

[Clem Cole]

As other have said - this was a serial port that was traditionally attached
to a DECwriter II so you had a paper trail.   If you look at the comments
in the kernel printf routine in UNIX will make note of saying this should
not be used for "chit-chat" because the kernel printf took over that serial
port and nothing else could get thru when it was typing at typically 120
cps on the DECwriter.

So as people have pointed out, simh supports the "console" typically a the
place where you are typing commands to simh after you start the the
simulation.

Two other points to consider...

1.) In a large computer center in the old days (with lots of systems in the
room), the console terminals took up a lot of space and might be in
different places.   So one thing that was often done was to instead of
connecting the console serial port to a DECwriter, but into a erial mux on
another system (often the size of PDP-11/34 with a DZ or DH on it) and suck
the console messages for each system into separate files for each system.
Then the operator would sit behind VT-100 or like and look at the log and
if need be, run a program that allowed him/her to connect to the input part
of any of a particular system and type in commands as appropriate.


2.) The idea of a console serial port still lives today if you any of the
Unix or Unix-Clones (e.g. Linux).   They have a way to boot the BIOS roms
to a serial port, which has typically been connected to another computer.
Besided getting the log, another nice thing about this set up is being able
to run a debugger on the console.

Clem

On Sun, Feb 14, 2016 at 3:11 PM, Zachary Kline <zkline at speedpost.net> wrote:

> Hi All,
>
> 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?
> I gather SIMH itself doesn’t do much terminal emulation, so it might be
> worthwhile sending the console output to another emulator which could
> handle the keyboard and such.
>
> I guess this depends quite a bit on the OS and machine in question too. :)
>
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