UNIX-PC 5620/dmd Emulator

[Stewart]

In article <284 at icus.UUCP>, lenny at icus.UUCP (Lenny Tropiano) writes:
> In article <3897 at ihlpf.ATT.COM> gmark at ihlpf.ATT.COM (Stewart) writes:
> |>Has anyone given any thought or does anyone know about a
> |>LAYERS emulator to allow a UNIX-PC 7300/3B1 to emulate a
> |>dmd 5620 or 630 terminal?  I seems as though it should be
> |>able to emulate a 5620 that just happens to never display a
> |>window larger than a 7300 screen.  A nice enhancement to this
> |>would be for it to emulate a full 5620 or 630 screen, but
> |>with a means to "grab" and "slide" the viewed window of the
> |>real screen over the full 5620/630 screen loaded in RAM.
> |>Possibly some hacking to the source in xt/layers.c?
> |>
> Can you explain what actually are you talking about?  Is this the xt/layers
> disk that is included in the 3.51 distribution?  I loaded it on, without
> any documentation on what it does (although I know you need a windowing
> terminal)  How do you get the 3B1 to emualate that?  Is that another
> software package?  Or is it included?  Can someone enlighten me on something
> I know *VERY* little about... Thanks..

For anyone who was confused by my posting, especially those who sent
me mail, here's hoping I don't waste your time on things you already know,
but am detailed enough to be helpful:

	There is a class of terminals - dmd (for dot-mapped-display)
like the AT&T dmd5620 and the 630 (probably others I'm not familiar with
as well) that support "layering" capability.  This just the ability to
support windows that can overlap.  The drivers for this type are called the
"xt" drivers, that basically are smart enough to know that there's one device
out there that is appearing as several terminals (the windows).  The
"xt" stuff called by "layers" in the 3B1 allows the computer to act as
host for these terminals.  HOWEVER, it doesn't (I THINK - hence part of 
the reason for my posting) allow the 3B1 (or 7300) to act as a dmd terminal.
Now, the screen for the dmd terminals have a lot more space (5620 has
about 800 by 1000 pixels and is 8 1/2 by 11 inches -- the 630 is about
30-50% wider), but the UNIX-PC could just look like a dmd that someone
just never draws a window bigger than about 7x9 inches on.  It would be
great to be able to use the UNIX-PC as a poor man's 5620.  It would 
be especially nice to be able to use things like "proof", which provides
a WYSIWYG interface to *roff typesetting stuff.  In other words, could
the emulator be written to provide an interface that looks like a dmd 
to SOFTWARE as well.  If a larger screen were REALLY needed, it would
be GREAT to be able to "slide" the UNIX-PC visible screen "around" the
"virtual" screen that exists in the UNIX-PC memory so as to be able to
see all of a big screen if absolutely necessary.  Hope this helps.


				G. Mark Stewart
				ATT-BTL Naperville, ix1g266
				ixlpq!gms 979-0914