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From: thad@btr.btr.com
Newsgroups: unix-pc.general,comp.sys.3b1
Subject: Re: Lots of weird hangs reported - could be a 3.51m bug?
Message-ID: <1645@public.BTR.COM>
Date: 7 Feb 91 13:12:54 GMT
Sender: thad@public.BTR.COM
Followup-To: unix-pc.general
Organization: BTR Public Access UNIX, MtnView CA, Contact: cs@btr.com 415-966-1429
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wilkes@mips.COM (John Wilkes) in <45628@mips.mips.COM> writes:

	I used to have the occasional odd hang and other strange occurences.
	Then I got a UPS.  System stays up for months at a time, and then
	comes down usually because of some pilot error or the power going away
	for longer than the UPS stays up.  I've been running 3.51m since about
	a week after it was available, and I've not noticed any problems with
	the machine up 24 hours a day.
	[...]
	My personal theory is that the 3b1's power supply is sensitive to the
	power coming from the line.  The $500 I spent on a UPS is one of the
	best investments I've ever made.

I second John's comments without hesitation.  From personal experience I can
state that unconditioned AC line power is ALL computers' nemesis.

I've posted (volumes) on this subject before, and have rented an AC power line
monitor to see 2000V spikes, hash, and other garbage on the power lines caused
by refrigerators, flourescent lamps, drill motors, etc. create "weird" and
"inexplicable" system problems.

At the MINIMUM, one needs an "adequate" surge and transient suppressor for a
computer.  And, I can say this without hesitation or fear of retribution or
lawsuit (because the technical facts attest and substantiate my comment): the
stuff from Radio Shack is JUNK and you don't want that stuff anywhere near your
computer.

After putting out bids and personally examining devices and reading the test
reports in various magazines, the surge and transient protectors I have on my
systems are those from GTE (cringe, yes, I know the 3B1 bears an AT&T logo :-).
But, since 1985, I have not had a SINGLE AC-power-related problem with ANY of
my computers, and I have a LOT of systems running here.  Prior to using the GTE
devices, I would get numerous floppy errors each week (and you don't want to
know the HD travails).

At this point in time, ALL my computers, modems and LANs are serviced by a
SAFE "UPS", and everything else (printers, plotters, phone lines, etc.) is
protected by GTE AC surge/transient suppressors.  When you consider that my
systems remain up for 6 months at a time with NO (repeat, NO) problems, that
should be sufficient testimony; and the only reason I mention "6 months" is
because that's the interval I've chosen for powering-down and cleaning the
fans and guts.

Thad Floryan [ thad@btr.com (OR) {decwrl, mips, fernwood}!btr!thad ]