Date: Thu Feb 25 20:29:06 1982
Subject: Tek 4112
>From cbosgd!mark@Berkeley Thu Feb 25 18:28:50 1982
I've just spent a week playing with a 4112. I have no idea what they
cost, but I assume it's mucho bucks. Since I'm not a graphics expert
and the only manual I had was the operators manual (they didn't give
me a programmers manual so I didn't have much detail on the escape
sequences) I can't really evaluate the graphics stuff. It seems to
have the usual 1K x .75K frame buffer (white phosphor, no flicker at
all, even with the screen full of text) and they alluded to some depth
(e.g. brightness control) of the pixels, but I couldn't find any
documentation to confirm the depth. It comes with a pair of thumbwheels
for a pointing device, with options including a tablet (with a stylus or
a mouse-style 4 button tablet pointing device), a floppy drive, 3 extra
rs232 ports in the back, and 3 planes of graphics memory. The terminal
weighs a ton! It's a desktop model but you need two people to carry one
across the room. It's quite big and the keyboard doesn't detach - just
as well, I don't think I'd want that heavy keyboard on my lap.
The remaining evaluation will discuss using the 4112 as a regular CRT
terminal - in particular an attempt to make a termcap for it. I'm
enclosing my final result at the end.
Basically, you can't run any existing screen editor on it. The best I
could do was run it in glass tty mode, allowing the one line open mode
in vi. For screen editing it's about as good as an adm3 (yes, a 3, not
a 3a.) The situation is as follows. There are two kinds of areas:
the dialog area (for text) and the other area (doesn't seem to have a
name) for graphics. They overlap - the other area takes up most of the
screen and has a fixed size; the dialog area can have up to 34 lines of
80 chars (default is 5) anywhere on the screen. It will remember a hundred
or so lines of history in the dialog area - you can scroll back into
it using the thumbwheel (this is nicely done).
In the dialog area, it understands return, linefeed, backspace, and bell.
There is also an escape sequence which clears the dialog area and homes
the cursor in it. There is no way to move the cursor up off the bottom
line, hence the inability to run a screen editor. (You could always clear
and redraw for every keystroke, but you couldn't put the cursor where it
belongs after drawing below it.)
It is also possible to do text stuff in the other area. There is a
clear screen sequence and even an (undocumented) cursor up command
(^K)! It should also be possible to address the cursor by pixel
addressing relative to the bottom left hand corner. Only problem is
that there is no way to scroll the graphics area. Now I suppose it
would be possible to repaint the whole screen here since you can put
the cursor whereever you want. (Using linefeed, return, up, backspace
and going right by typing over the character you're moving over.)
But this would require an enhancement to vi that I didn't want to
mess with. I wonder if any of the emaxen can handle this?
I talked with at least 3 people from Tektronix trying to get this to
work. When I told one of them I wanted to move the cursor around,
he told me "If you wanted to do that, you should have gotten a 4025!"
I dunno. It may be a wonderful graphics terminal, but it seems to me
that a person working on graphics might want to edit his graphics
program, and he shouldn't have to get a second terminal for that.
Other random braindamage: instead of "smooth scroll" (ooze) mode, this
terminal has a notion of acceleration and deceleration. If you are
trying to scroll through a file with a wait for input after every page,
it will gradually speed up through the first 3 or 4 lines, zoom through
the middle of the page, and then gradually slow down for the last few lines.
Also, when it hits the end of the page in the dialog area, you have four
options for what happens:
(1) it clears the screen and keeps going
(2) it waits for you to hit page and then keeps going
(3) it makes a hard copy and then keeps going
(4) it sends a BREAK to the computer (you might be able to program this
to send something else) and then keeps going.
(I think the terminal does xon/xoff when necessary.) Left off the list
is for it to scroll the dialog area up. It seems to scroll if you have
typed something within the last page, but if the computer's just dumping
stuff out at you, it will clear the screen regularly. (I did a
"cat /usr/dict/words" on it and it really weirded out - cleared the screen
for the first several screenfulls, then started flickering a few characters
in the upper left corner, then when I hit DEL to abort, every time I hit del
it redrew the screen, one line further in the dictionary! Eventually it
got into a mode where it printed lines of the dictionary out, scrolling
properly, at about 600 baud (I was was running at 9600) and then printed
all the output from my hitting DEL.)
Here is the termcap I came up with. Only the vanilla entry is tested.
The screen size for the non-dialog area is probably wrong - I don't think
the number of lines in that area is an integer!
# The 4110 series may be a wonderful graphics series, but they make the 4025
# look good for screen editing. In the dialog area, you can't move the cursor
# off the bottom line. Out of the dialog area, ^K moves it up, but there
# is no way to scroll.
Xs|4112|4113|4114|tek4112|tektronix 4110 series:\
Xt|4112-nd|4112 not in dialog area:up=^K:ns:cl=\E^L:tc=4112:
Xu|4112-5|4112 in 5 line dialog area:li#5:tc=4112:
Date: Thu May 13 01:00:26 1982
Subject: more on the Tektronix 4112
Posted: Wed May 12 10:19:26 1982
Received: Thu May 13 01:00:26 1982
>From cbosgd!mark@Berkeley Wed May 12 10:13:25 1982
A while back I reviewed the Tek 4112 and concluded that the graphics may
be OK, but the alphanumeric capabilities were like a totally dumb glass
tty, which couldn't run a screen editor. When that review went out, I
started seeing amazing results from inside Tektronix. Seems they get
this stuff, and are very interested in fixing such deficiencies.
They have a floppy which runs a program that will emulate a vt52 in the
4112. The program is unsupported but it's free. I played with one for
a few days, and it emulated a vt52 fine except that characters overstruck
instead of replacing what was already there. (Clr to eol/eos worked fine.)
This made the terminal usable with vi, but you had to hit control L a lot,
since vt52's don't have insert/delete line/char.
I don't have access to the terminal anymore, but I'm told that there is a
setup mode flag in the 4112 part of the terminal (not the vt52 emulation)
that causes replacement instead of overstrike in the graphics area. This
is claimed to fix the problem.
Tek says it's working on a full ANSI standard alphanumeric implementation
for the 4112 right now, so the terminal will be going from famine to feast.
They don't have an announced date, but seem to think it will be available
in a few months. It will be possible to upgrade old 4112's by loading a
floppy or replacing the roms. Tek is aware that the cursor addressing
sequence in the ANSI standard is verbose, and seems likely to include
a 4 character sequence as a short synonym.
If you already have a 4112, and you like to use screen editors, it seems
worthwhile to get the floppy. If you are thinking of getting one, you
probably want to wait for the ANSI version.