Xref: utzoo comp.periphs:1606 comp.sys.mac:28227
Path: utzoo!utgpu!utstat!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!rutgers!bellcore!texbell!uhnix1!moray!siswat!buck
From: buck@siswat.UUCP (A. Lester Buck)
Newsgroups: comp.periphs,comp.sys.mac
Subject: Re: Impulse drives from Quantum/Plus
Summary: SCSI standard can be very high performance
	 current SCSI implementations can be greatly improved
Message-ID: <379@siswat.UUCP>
Date: 12 Mar 89 21:41:28 GMT
References: <1397@ccnysci.UUCP>
Organization: Photon Graphics, Houston
Lines: 25

I didn't read the Infoworld article, but does this guy work for 
the company making Cluster Disk Interfaces?  He sure doesn't
understand SCSI...

For a glimpse of the future of SCSI, check out the Winter 88
issue of Computer Technology Review (call 213-208-1335 and ask
for a copy, and a (free :-) subsciption ).  In an article titled
"Future High Performance Systems Profit Through Use of SCSI
and VMEbus", two guys from Emulex explode several common
myths about SCSI.  They also present a fascinating timing
path for a complete typical SCSI command, showing every delay incurred
at all four levels (application/OS, driver, host adapter, and
SCSI target).  It turns out that the Unix buffer cache search is
about 30% of the total transfer overhead today, and the
requirement that the target check every bit of the SCSI
command data block parameters for validity is another 30%
or so.  Really fancy SCSI protocol chips will be able to
do this check in the future.  And with SCSI-2 offering
up to 40 MB/sec, the future of SCSI is very bright.

The design of SCSI has few inherent limitiations, but the current
implementations can leave much to be desired.

-- 
A. Lester Buck		...!texbell!moray!siswat!buck