[Simh] Serial Console

[Ethan Dicks]

On Tue, Jul 3, 2012 at 7:55 AM, Johnny Billquist <bqt at softjar.se> wrote:
>>> On 2012-07-03 11:49, Mark Benson wrote:
>>>>
>>>> Simple question: Can SimH's CONSOLE output be directed to a Serial port
>>>> (i.e. via /dev/ttyS0)?
>>>
>>> I think I looked into this a few years ago, and found that it can't...
>
> However, how do you change the speed of a serial port? Or detect the modem
> signals? Or any other direct manipulation? That is way different on
> different systems.

Yes.
>>> However, I think that under Unix, if you just log in on a serial port and
>>> start simh, you'd be more or less there already?
>>
>> No, you see what I would like to do is connect a VT terminal directly
>> to SimH to use either as the OP console...

That's the easy one - You have to get the dumb terminal working with
your base OS (UNIX, Linux, whatever), _then_  "just" log in and fire
up SimH.  Your SimH console session will emit through your OS's serial
driver and pass along whatever characters your emulated-system
generates and the dumb terminal will act upon them.

I had to do this with klh10 because xterm windows are just not
VT100-ish enough to run emacs.  I had zero problems with a real VT220
hanging off of a serial port on a laptop, logging into the Linux
laptop after starting a getty process, then running klh10.  SimH would
be the same.

>> or to provide a real VT access
>> for the DZV11 emulation. This is all about cutting out multiple layers
>> if terminal emulation to get real VT interaction direct to the
>> emulator.

Not sure how one could do this without a lot of work on the DZ(V)11
emulation code.

>> The reason is I have noticed that over Telnet VMS is pretty robust but
>> only offers a 'cut down' cinnection to remain compatible. Conversely,
>> GNU screen working directly as the console convinces VMS that it's a
>> real VT then it pukes when you run something like EVE or
>> TCPIP$CONFIG.COM because VMS is assuming the terminal can handle
>> features that screen cannot. There are also other things like
>> softloaded fonts etc that only real VT terminals handle properly that
>> break ir don't work in screen or telnet.

Yes.  Same problem I had with emacs and klh10.

> Well, get a proper terminal emulator... :-)
> Apart from the soft font thing, I'd say that xterm is what you want. It's
> the only terminal emulator that I have found which actually emulate a VT100,
> VT102 or VT220 correct. But you do not have soft fonts...

It's not close enough for some applications.  It works 95%+ of the
time, but editors are notorious for taking advantage of specific
terminal "behaviors".

> Grab your VT510, connect it to your Unix system on a serial port. Log in to
> Unix. Telnet into simh, and voila!

That might work as long as what you are doing isn't intercepted and
modified by the telnet layer (including the client on the terminal
end).  95%+ will be fine - it's that last bit that can make or break
the experience.

-ethan