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We received a very attractive offer for some Digital Engineering HiScan
terminals. The company has gone out of business, and a local dealer
purchased several dozen of these. I tested both color and monochrome
(grey-scale) models, and performance comparisons are given below with
the recently-reviewed Plessey and Encore terminals.
The HiScan terminals are modified DEC VT240 (monochrome) and VT241
(color) terminals. Although the monitors are still labelled
``Digital'', they have been internally modified, and therefore cannot
be serviced by DEC. The controller box is separate, like on the DEC
products, but is somewhat smaller. The keyboard is a standard DEC
VT240 keyboard, and the setup options are very similar, though extended
to support new features.
HiScan 4210:
* monochrome
* alphanumeric resolution: 80/132H x 30V (cf. DEC 24V)
* graphics resolution: 800H x 600V (cf. DEC 240V)
* 4 gray levels
* proprietary bit-slice graphics processor
* non-interlaced 60Hz 12in modified DEC VR201 monitor
* emulates: VT100, VT52, VT240, VT640, Regis, and Tektronix
4010
HiScan 4205:
* color
* alphanumeric resolution: 80/132H x 30V (cf. DEC 24V)
* graphics resolution: 800H x 300V (cf. DEC 240V)
* 4 colors displayable from palette of 64
* proprietary bit-slice graphics processor
* non-interlaced 60Hz 14in modified DEC VR241 monitor
* emulates: VT100, VT52, VT240, VT640, Regis, and Tektronix
4010, and optionally either color 4107 or 4105
The DEC VT240 monochrome terminal has a current list price of $1980,
and the color VT241 lists at $2980. These HiScans are available to us
for about $1000 in either monochrome or color, which is an extremely
attractive price for a graphics terminal, particularly considering the
extra graphical and alphanumeric resolution.
The review of the DEC VT24x terminals elsewhere in this file was very
negative, pointing out several problems. The most serious was the
inability of the terminals to function above 2400 baud without data
loss. I am happy to report that the HiScan terminals worked without
any data loss at 9600 baud in both graphics and alphanumerics tests
with no flow control in effect; this makes them quite usable for EMACS.
The DEC terminals are also rather slow in graphics mode. Function keys
on the HiScan terminals can be loaded locally as well as from the host,
and can be saved in non-volatile memory; on the VT24x terminals, they
can only be host-loaded, and are volatile.
Here are some speed comparisons with the Plessey and Encore terminals.
This table appears without the HiScan entries in the Plessey review.
``Vector drawing performance of any graphics terminal is very
important, so several tests were made comparing the PT-100G
with the Encore HostStation 110, which so far has been the
fastest graphics terminal I have found. The first set drew
1025 horizontal, vertical, and diagonal lines on a square
filling the shortest extent of the screen; this tests
performance of the vector drawing for long vectors. If special
case code has been developed for the case of dots falling into
consecutive memory locations, one would expect that at least
one of these should run 16 to 32 times faster. Neither the
PT-100G nor the HS-110 have this optimization. The second set
of tests are Sierpinski curves from DEM81 in Cartesian, plane
polar, and elliptical coordinates; these emphasis short vector
performance, with about equal numbers of horizontal, vertical,
and diagonal vectors.''
-------------------------------------------------------------------
Test PT-100G HS-110 HiScan mono HiScan color
(sec) (sec) (sec) (sec)
-------------------------------------------------------------------
horizontal 17 12 14 12
vectors
vertical 15 12 14 12
vectors
diagonal 31 14 15 14
vectors
Sierpinski 63 60 61 71
Cartesian
Sierpinski 101 101 105 103
plane polar
Sierpinski 102 102 103 108
elliptical
-------------------------------------------------------------------
The HiScan is therefore comparable in performance with the Plessey and
Encore terminals, although the pixel drawing rate is necessarily lower
because of the reduced screen resolution (56% of the HS-110 in
monochrome, 28% of the HS-110 in color). Considering the relative
prices of these terminals, the Digital Engineering terminals can be
rated a good buy in color; in monochrome, the Plessey is close enough
in price that it is a better buy.