bcw (06/14/82)
From: Bruce C. Wright @ Duke University
Re: Graphics terminals
We are evaluating different low-cost raster graphics terminals
for Duke Medical Center, and have not been impressed by any of
the terminals which have come to our attention. The intent is
to purchase several copies (3-9), so price is somewhat important
(ie we can't afford $9k and up). Ideally, the terminal should:
o Cost in the neighborhood of $2500-$4000;
o Have resolution in the neighborhood of 512 x 512 or
higher;
o Be reasonably cleanly implemented from a hardware and
software standpoint, including ease of maintenance;
o Have the ability to have an attached hard copy unit
for duplication of graphics (at an added cost, if
necessary);
o DEC CRT (VT-100, VT-52) compatibility would be
desirable since these terminals will probably spend
a great deal of time attached to DEC systems which
have a rather closed-minded view of what a CRT terminal
should look like;
o Color is nice but definitely non-essential; it comes
at a much lower priority than any of the above items.
We have looked at four basic options, but are not fully satisfied
with any of them:
o DEC VT-125;
o Selanar Graphics board for VT-100, C-Itoh, etc;
o HP-2648;
o Retrographics
The advantages/disadvantages of these terminals are:
VT-125:
Advantages:
-- DEC compatible
-- Reasonably clean hardware implementation
-- High level commands available to reduce communications
overhead
-- 4 gray scale allows multiple shades of gray or a color
monitor to be attached with up to 4 colors at a time.
Disadvantages:
-- Low resolution (240 x 768)
-- Suffers from astigmatism (horizontal lines are stronger
than vertical lines -- probably a result of the uneven
aspect ratio in its resolution).
-- Control sequences are extremely wordy causing more
communications overhead for simple commands
Selanar graphics upgrade for VT-100, C. Itoh, etc:
Advantages:
-- DEC compatible
-- Tektronix compatibility mode available
-- Native mode command set has medium level commands
available to reduce communications overhead
Disadvantages:
-- Low resolution (240 x 1024)
-- Suffers from astigmatism like VT-125
-- Hardware implementation is messy
HP-2648 etc:
Advantages:
-- Medium range resolution (360 x 720)
-- Tektronix compatibility mode available
-- Native mode command set has medium level commands
available to reduce communications overhead
-- Reasonably clean hardware implementation
Disadvantages
-- Cost (a reasonable system seems to cost > $5000)
-- Not DEC-compatible
-- Some commands need significant padding at high
baud rates
Retrographics:
(We have not had sufficient time to evaluate this
terminal, so we are not sure of all its advantages
or disadvantages)
Advantages:
-- High resolution (512 x 768 approx)
-- Tektronix compatibility available
-- VT-100 upgrade can be made DEC-compatible
Disadvantages:
-- Slow phospher screen could be annoying
-- Some people dislike the green CRT screen.
Are we missing any significant products in our price range?
Has anyone had any experience (positive or negative) with
any of the above terminals or with any other terminals in
the same performance class? Any comments anyone has would
be welcomed.
Please reply to me, not to the net; I will summarize the
results (if any).
Bruce C. Wright @ Duke University