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From: riddle@woton.UUCP
Newsgroups: unix-pc.general,comp.sys.att
Subject: Re: 3B1 and flaky power
Message-ID: <949@woton.UUCP>
Date: Tue, 17-Nov-87 17:18:20 EST
Article-I.D.: woton.949
Posted: Tue Nov 17 17:18:20 1987
Date-Received: Fri, 20-Nov-87 21:48:39 EST
References: <942@woton.UUCP>
Organization: Shriners Burns Institute, Galveston
Lines: 82
Keywords: surge spike brownout blackout
Xref: utgpu unix-pc.general:27 comp.sys.att:1556
Summary: Summary of email responses
Supple-Power: "Bob"


Last week I asked for advice about the advisability of putting a UNIX
PC in my home given a rather unreliable power situation.  Here are some
of the reponses I received. 


Darryl Wagoner (dpw@unisec.usi.com, ihnp4!rayssd!unisec!dpw):
>> The 3b1 has the best power supple of any computer I have seen.  I have
>> seen it take "blink" in power that has knock out my VCR, and every computer
>> at where I use to work (which includes 11+ Vax's, 4 Suns, and a Pyramid).


Brian Kantor (brian@sdcsvax.UUCP):
>> The 3B1/7300 draws about the same amount of power and has the same type
>> (switching inverter) of power supply as an IBM PC.  These are
>> relatively robust supplies, and not difficult to repair.  Unless you
>> regularly experience surges on your power line (lights flashing
>> BRIGHTER), you probably won't have problems.
>> 
>> If your power is really bad, you might be able to find a Sola Corp
>> constant-voltage transformer in some surplus house, or buy a power
>> conditioner that has one in it.  They'll eat most line surges and fix
>> brownouts, so they might be worth hunting up.  I'll bet they're not
>> cheap new.  Check the Inmac catalog to find out availability; don't buy
>> it from them because you can probably get it cheaper elsewhere.


P. Trent MacDougall (watmath!dalcs!dalcsug!ptmcd, iisat!tmpor!trent):
>> Just to tell you a little about what has happend to me.
>> 
>> My room is in the basement of our house, and when the water pump comes
>> on the lights go dim for a sec.  Well I thought nothing of this.  I
>> hooked up my 3b1 and after about 1 week it crashed.  I tried things
>> again and it crashed in about another week.  Needless to say I was very
>> unimpressed with the situation, so I called AT&T.  They couldn't tell
>> me anything and wanted to swap the motherboard (what else is new :-). 
>> After it crashed one more time I was starting to panic (addr fault in
>> kernel) myself; so while I was thinking about what to do the pump came
>> on and it hit me.  Sure enough, I ran a cord upstair where the 3b1
>> would be on its own circuit and it was up for 37.5 days without doing
>> anything to it; it didn't crash this time but it locked up.  Prob. 
>> this time because of the power company. 
>> 
>> So after saying all that, the 3b1 is very sensitive to fluctuations in
>> power.  If your machine crashes alot with `panic: addr fault in kernel'
>> that could very well be your prob. 


Olaf I. Henjum (ihnp4!ihlpf!olaf):
>> Probably your best SHORT-TERM solution will be to make a copy of your
>> (10-sector-format) diagnostics floppy and make SURE that that copy is
>> in the disk drive ALL THE TIME (unless of course you're using it for
>> something else).  This will at least reduce ALMOST to zero the chances
>> of your software getting scrambled by multiple power cycling of the hardware.
>> Why?  Because IF there is a floppy in the disk drive when the machine goes
>> down from a power hit, it will (when the power comes back on) try to boot
>> itself off of the floppy (rather than off of the hard disk).  If you get
>> 5 power hits in 15 minutes (for example), this can be the difference between
>> losing a few temp files (through fsck et al) and scrambling your entire hard
>> disk.
>> 
>> LONG-TERM, you do need to do something to protect the PC from:
>> (a) power surges (relatively cheap),
>> (b) (optional but still a good idea) power hits (not so cheap, as we're
>>     talking about an uninterruptable power source that fits on a 120V line).
>> 
>> I don't have any specific products to recommend here.  Sorry about that.


Dave Levenson (ihnp4!westmark!dave):
>> I recommend the TrippLite BC-425.  This unit conditions the power
>> line by absorbing spikes, and providing up to 30 minutes of standby
>> power from internal batteries.  List price is $595.  I sell one with
>> every PC network server I install.  See if you can find a local
>> supplier.  (If not, I can offer it at $525 + shipping.)


Thanks, everybody!

--- Prentiss Riddle ("Aprendiz de todo, maestro de nada.")
--- Opinions expressed are not necessarily those of Shriners Burns Institute.
--- riddle@woton.UUCP  {ihnp4,harvard}!ut-sally!im4u!woton!riddle