Xref: utzoo comp.unix.i386:5595 comp.periphs.scsi:582
Path: utzoo!utgpu!watserv1!watmath!att!pacbell!pacbell.com!ames!mailrus!uunet!xstor!billbr
From: billbr@xstor.UUCP (Bill Brothers)
Newsgroups: comp.unix.i386,comp.periphs.scsi
Subject: Re: SCSI vs ESDI
Message-ID: <186@xstor.UUCP>
Date: 4 Jun 90 18:12:35 GMT
References: <1990May23.151746.18784@cbnewsm.att.com>
Reply-To: billbr@xstor.UUCP (Bill Brothers)
Followup-To: comp.unix.i386
Organization: Storage Dimensions, Inc.
Lines: 35

In article <1990May23.151746.18784@cbnewsm.att.com> dab@cbnewsm.att.com (david.a.berk) writes:
>Subject line says it all, which is superior ?
>
>
>Dave Berk
>att!emdbl1!dab

Although the question is similar to "Which is better - single or married?",
I will try to put some of the good/bad info so a reasonable person could
further find facts and make a decision...

IF you are only ever going to run one disk drive on a single-tasking OS,
your answer is fairly clear -- ESDI. Otherwise, the answer is -- cloudy.

At somewhere around two drives and somewhere around 10 concurrent
processes, SCSI gets faster than ESDI. This break-even point can be
calculated if the EXACT application mix is known. The break-even
point is a function of when the paypack of disconnect-reconnect is
greater than the overhead of the SCSI structure. Another variable
thrown into the fray for fun has to do with how intelligent your
host adapter is and etc. etc.

My personal belief is that for simple systems that will never outgrow
one disk, ESDI or IDE is fine. However, for more complex systems that
will need more and more storage, mirroring, fault-tolerance, or other
advanced features, SCSI is definately the winning side.

Remember, people yelling "tastes greate/less filling" may both be
right...

Bill Brothers
Product Engineering Mgr.
Storage Dimensions, Inc.
Voice (408) 379-0300
billbr@xstor.UUCP or uucp!xstor!billbr