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From: mwg@petrus.UUCP (Mark Garrett)
Newsgroups: net.database,net.graphics,net.works,net.med
Subject: Re: ethernet in a hospital
Message-ID: <783@petrus.UUCP>
Date: Fri, 27-Dec-85 11:56:23 EST
Article-I.D.: petrus.783
Posted: Fri Dec 27 11:56:23 1985
Date-Received: Sat, 28-Dec-85 01:45:30 EST
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++
> > This may seem very silly.  It did to me when I was told but...  A close
> > friend of mine who does consulting work in the areas of communications,
> > networking and UNIX was once working with a hospital.  They ruled out
> > use of ethernet because it is expected to have failures (i.e.
> > collisions) and they were afraid that some clever lawyers might label
> > this as negligence.  Lawyer to jury:  "this institution installed a
> > system expected to have periodic failures which would delay critical
> > patient information.  Yet they tell you they care about their
> > patients".  Yes I know it's ridiculous but that was their concern.
> > You can bet the lawyer would carefully pick a technically naive jury.

> But there has been
> no problem from the legal department about the use of ethernet. All systems
> can break. Negligence is failing to provide a reasonable (electronic or
> otherwise) backup for when the system does break.

Somehow I would expect that even a lawyer [:-)] could explain the
reliability of ethernet in layman's terms.  It is incorrect to
consider a collision to be a failure in any sense.  The transport
and network layer protocols must insure that colliding messages
are re-sent accurately.

The CSMA/CD (ethernet protocol) scheme can be compared to trying
to place a call on the phone.  Just because you sometimes get a
busy signal doesn't pmake the phone an unreliable system.  In
both cases there is an unbounded upper limit to the actual
time of connection.  But since the probability of not connecting
diminishes very rapidly with time (repeated trials), it is still
a useful and reliable system.

The system should also take care of real failures.  For instance,
if the cable is broken or the station you are talking to goes
down, your computer should not lead you to beleive that the
message was sent sucessfully.

-Mark Garrett