Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!prcrs!paul
From: paul@prcrs.UUCP (Paul Hite)
Newsgroups: comp.sys.hp
Subject: Re: HP-IB or SCSI disks for a 300 series?
Message-ID: <1270@prcrs.UUCP>
Date: 2 Nov 90 16:50:30 GMT
References: <1413@limbo.Intuitive.Com>
Organization: PRC Realty Systems, McLean, VA
Lines: 26

In article <1413@limbo.Intuitive.Com>, taylor@limbo.Intuitive.Com (Dave Taylor) writes:
> I found that a bit surprising, but somehow it *does* have the ring
> of validity, so ... what's the gig?  Is this true?  Will a fast HP-IB
> disk perform as well as a fast SCSI disk?

Well we use 800's and we don't use SCSI.  But we did run some tests on
HP-IB vs. HP-FL.  Roughly, we found that HP-IB can easily handle a 
single HP disk.  It can be the bottleneck with 2 disks that are maxed
out, but not by much.  With 3 maxed out disks it is definately a bottle
neck.  Let me stress that our test involved disks 100 % busy.  We  often
limit HP-IB links to 2 disks as a result of our tests.  A single maxed out
disk did not perform much better on HP-FL than it did on HP-IB, but we
could detect a difference of a few % with very large reads.  HP-FL can
handle 4 disks without being a bottleneck.  We did not explore HP-FL's
upper limit beyond that.

> If that's the case, then what's the fastest, most reliable, HP-IB 
> disk available today, from HP or otherwise?  What's it list for?  

All of HP's disks seem rather similiar in performance.  And they are
so reliable that we can hardly believe it.  We are still waiting to 
lose our first byte of data due to the failure of an HP disk drive.
(And I don't feel a need to knock on wood! :-)

Paul Hite   PRC Realty Systems  McLean,Va   uunet!prcrs!paul    (703) 556-2243
        You can't tell which way the train went by studying its tracks.