Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!zaphod.mps.ohio-state.edu!wuarchive!uunet!pdn!tscs!metran!jay
From: jay@metran.UUCP (Jay Ts)
Newsgroups: comp.unix.sysv386
Subject: Re: Need Recommendations On 386/486 UNIX systems
Keywords: unix, 386/486
Message-ID: <365@metran.UUCP>
Date: 29 Dec 90 05:17:52 GMT
References: <1990Dec22.143706.4493@virtech.uucp> <358@metran.UUCP> <1990Dec24.152633.5195@bilver.uucp>
Organization: Metran Technology, Tampa, Florida
Lines: 58

In article <1990Dec24.152633.5195@bilver.uucp>, bill@bilver.uucp (Bill Vermillion) writes:
> In article <1990Dec23.162033.3287@virtech.uucp> cpcahil@virtech.UUCP (Conor P. Cahill) writes:
> >In article <358@metran.UUCP> jay@metran.UUCP (Jay Ts) writes:
> >>One of my clients suffered a direct lightning strike to their building this
>  
> >From my experience this is a very rare occurence (not lightning striking, but
> >lightning strikes causing damage to serial port cards). 
>  
> >>Arnet reports that 70% of their cards were returned due to surges on the
> >>serial lines.
> 
> Gawd - I hope they meant 70% of the returned cards were due to surges ...
> That I can understand, but having 70% of the cards returned ... ?

Erps!  I guess I must have wrote that wrong!  To restate for clarity, 70% of
the returned cards failed due to surges on the serial lines.

> >The other way to look at it is that maybe the arnet boards are soo bad
> >that the blow apart form the smallest voltage spike or short.

The problem is with the industry standard line driver chips I wrote about
earlier.  These chips, 1488 and 1489 line drivers and line receivers, are
prone to failure due to surges.  They are used not only by multiport cards,
but also Wyse 60 and other terminals and computing equipment.  See below.

> Three Wyse 60's had some problem, one of which would receive but not
> transmit.      

I'll bet anything that you can find a blown 1488 chip in them.  I've seen
this problem both in the system that was hit by lightning and another
client's system (which was not).  BTW, on the terminals we opened up, we
found that some of the 1488/9's are socketed.  Wonder why...

> >Don't take me wrong.  I'm not saying how good or bad the arnet cards are. 
> >I'm only saying that lightning is not a major concern for day to day 
> >operations of a "normal" system (of course if the system must have 100%
> >uptime even in the worst set of conditions AND the client is willing
> >to pay the price,  you can use the extra money to provide lightning
> >arrestors).
> 
> Lightning is fickle.  It is non-predictable, and never appears to do the
> same things twice (except hit twice in the same place!).

Here in Florida, it *does* do that!  I guess I should have pointed out
earlier that I am working in southern Florida, which is the lightning capital
of the U.S.  Hence I am very conservative in my opinions regarding surge
protection.

I may seem to be worrying too much, but think about how much it will cost
in downtime alone if a system is damaged by a single lightning strike or
other power surge.  Now I'll leave you with some time-honored advice:

"An ounce of prevention is worth a pound of cure."
"A stich in time saves nine."

				Jay Ts, Director
				Metran Technology
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