moving CPUs far away

Mike Muuss mike at BRL.MIL
Sat Oct 21 10:11:10 AEST 1989


SGI has told us that 75' of cable is the "design limit" for good quality
on the Iris machines.

Personally, I can't stand the noise of the CPUs, so I *always* remote my
Iris.  Usually I use the 75 foot cables that we pay SGI to provide us.
In one circumstance, I had to remote my display about 175 cable feet.
The image was still surprisingly good at that distance, although the
fact that the cable was run over the fluorescent light fixtures for about
80 feet of that resulted in some 60 Hz noise being picked up, but it
was tolerable.

If you have a processor that will be running a (video) film recorder,
or driving an RGB-to-NTSC converter for video tape, do NOT remote that
display.  Keep your video cable lengths as short as possible, and use
the best coax you can afford.  (There is a special kind of Belden coax
to use for this purpose, I don't recall the number off hand).

The astute eye (and ear, for sound) can see (hear) almost any kind of
regular noise in the signal.  (If you think I sound fanatical about
video quality, you should hear the lengths I take to preserve sound
quality).

I have no experience rack-mounting SGI equipment.  For that, you need a
mechanical engineer.
	Best,
	 -Mike



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