[unix-pc.general] xt/layers

jet@flatline.UUCP (j. eric townsend) (10/28/89)

Just what is it?  wtinit says I must run it from a "DMD terminal"...



-- 
"I imagine you know about as much about deconstruction as I do programming
in assembly language." -- Thomas Maddox
J. Eric Townsend uunet!sugar!flatline!jet com6@uhnix1.uh.edu
EastEnders Mailing list: eastender@flatline.UUCP

john@banzai.PCC.COM (John Canning) (10/30/89)

In article <2502@flatline.UUCP> jet@flatline.UUCP (j. eric townsend) writes:
>
>Just what is it?  wtinit says I must run it from a "DMD terminal"...
>

xt/layers runs with the AT&T 615 and 630 terminals.  It allows you to
run several processes from one terminal (aka the suspend function key
on the main console).  It fulfills the original marketing hype that
one could use the suspend key from remote terminals.

With the 615 terminal, you use the function keys to create a new window.
Using the local CPU inside the 615, you can resize the window, and
reposition it on the screen.  You can have either 3 or 5 windows (I
forget which is the maximum number).  If the window is active and
takes up the entire screen, then you cannot see any of the other windows.
Otherwise, you can have several windows on the same screen, and as
output goes to each window it is updated.

Output is sent to the terminal in packets, and each packet is tagged
for a specific window.  The 615 will update a window inside its own
memory even if it is not being displayed at the time.  So, xt/layers
acts as a bit of a multiplexer...

AT&T offered an upgrade to the 610 terminal to make it a 615 multi-
tasking terminal.  It cost about $80.

I found xt/layers to be a bit on the slow side.  Although several of
our customers have 615 terminals, none of them are using xt/layers.

With the 630 terminal, you can write your own drivers for the terminal
itself, and download them to it.  At a recent Unix convention, I
saw some pretty neat "layered" displays on the 630 with both the
6386 and 3B2 family of computers.

John Canning					...uunet!uvm-gen!banzai!john
The People's Computer Company			...attmail!banzai!john
Williston, Vermont				john@banzai.pcc.com
802-864-0747

wtr@moss.ATT.COM (3673,ATTT) (10/30/89)

In article <1989Oct30.063026.8242@banzai.PCC.COM> john@banzai.PCC.COM (John Canning) writes:
>In article <2502@flatline.UUCP> jet@flatline.UUCP (j. eric townsend) writes:

>>Just what is it? [layers]
>>wtinit says I must run it from a "DMD terminal"...

>xt/layers runs with the AT&T 615 and 630 terminals. 

The entire family of DMD terminals (all by AT&T) includes the 
old Teletype BLIT, the 5620, the 615, 620, and 630.  These terminals
allow you to download a basic window manager for the terminal for
the host computer.  programs (editors, previewers, games) can be
downloaded onto the terminal to run.  on my 630 at work i have a
troff previewer and a bitmap editor currently loaded.

the old 5620 terminal uses an mc68000 processor for management.
i believe that the 630 is the same.

>It allows you to
>run several processes from one terminal (aka the suspend function key
>on the main console).

the method used is similar to that of shell layers (shl), in that a
number of "virtual devices" (/dev/xt### in this case) are created
and i/o to the terminal is done through these)

>I found xt/layers to be a bit on the slow side.  Although several of
>our customers have 615 terminals, none of them are using xt/layers.

The  "slowness"  can also be attributed to the fact that all this
communication is still run over you standard serial line.  we
are not dealing with that great a bandwidth.


>John Canning	
--
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was: Bell Labs, Whippany NJ				att!bromo!wtr
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