8.10.1: Large format image display and hardware for DEIMOS
The graphics interfaces for all of the options discussed below
have servers for the X Window System. Use of a dedicated image display
without X could result in better performance, but the costs of
creating non-interoperable software for unique hardware do not
justify such an effort. The X Window System has advantages of
portability, interoperability, and familiarity. DEIMOS image display
will use the X Window System.
DEIMOS direct images will be roughly 8k x 3k pixels. DEIMOS spectral
images will be 8k x 8k pixels, although it seems likely that these
will be stored as four 2k x 8k images. These images are larger than the
pixel resolution of all existing monitors. During typical operation
at the summit there could be a desire to display two DEIMOS images with
one as quick-look and another for reduction.
Commonly available high resolution monitors for computers have no more than
1280 x 1024 pixels. This implies binning by a factor of 8 to display
an entire image. Commercial availability of HDTV will not solve this
problem because its vertical resolution does not exceed currently
available monitors. The advantages and costs of various possibilities
are described below.
8.10.1.1: 2k x 2k Monitors
2k x 2k monitors are currently a specialty item used only in a few air
traffic control and satellite imaging operations. These monitors
require hardware interface cards to the CPU and X server software
tailored for that hardware. (One vendor supplies a complete hardware
solution that plugs directly into an s-bus slot of a Sun or a
u-channel slot on IBM. Others provide frame buffer cards intended
to fit in a separate 6U VME chassis.)
item cost
1 2k x 2k monitor $32000
1 graphics interface card + SW $5000 - $10000
1 keyboard & mouse counter top space
1 bus slot [optionally]
[or] 1 6U VME chassis with CPU $$$$
A few systems exist where these 2k x 2k monitors have been arrayed
into a video wall of 4k x 4k pixels. However the costs of such a
system are beyond the DEIMOS budget. It is unlikely that spare
hardware components could be purchased, so this system would be
unique.
8.10.1.2: Arrays of commonplace monitors
X server software which can drive multiple screens as a single display
is freely available for Sun platforms and commercially from Quadrate
and X/software
for several other brands of CPU. A desktop Sun system can accommodate
up to 4 additional graphics S-bus cards. These could be stacked into a
2x2 video wall with the original console at the side. This
arrangement provides a display surface of 2560x2048 pixels plus the
original console. The price of such a video wall would be less than
for a single 2k x 2k monitor, but it would effectively consume an
entire machine.
There are various possible configurations for such monitors.
A workstation's original monitor could be supplemented by 4 more to
give an image interaction array plus a console; or by only 3 screens
to produce a 2x2 array; or simply add one extra monitor and bin
by a factor of 8.
N 19-inch hi-res color monitors $2500 each
N graphics interface cards $800 each
N bus slots
N times 2 Mbytes of memory $80 each
software license from vendor $1000
8.10.1.3: Analysis
Even the best conceivable hardware would still require binning of the
image and interaction with more than one window. For this reason the
software for image display and interaction should make it easy to
place a full frame image in one window and a zoomed image in another
window. It should be possible to place different windows on different
X screens or even on different X servers. This will permit operation
of the software with any configuration of color X hardware.
Steve Allen <sla@ucolick.org>
$Date: 1996/03/18 23:40:21 $