Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!bu-cs!encore!pinocchio!terryk
From: terryk@pinocchio.Encore.COM (Terence Kelleher)
Newsgroups: comp.periphs
Subject: Re: Holy Bus Wars (ESDI, SCSI, SMDx, IPIy, UTTERz)
Keywords: SCSI ESDI measurements
Message-ID: <3918@encore.UUCP>
Date: 19 Oct 88 14:53:49 GMT
References: <2472@alliant.Alliant.COM>
Sender: news@encore.UUCP
Reply-To: terryk@pinocchio.UUCP (Terence Kelleher)
Distribution: na
Organization: Encore Computer Corp, Marlboro, MA
Lines: 20


Good points on system overhead.  Sorry I had not said it myself.  It
is these basic physical delays tend to level all.  

The > 1.5 MBPS async rates on SCSI are limited in actual use.  The
speed slows significatly as cable lengths increase and the high speeds
are usually only available when the host and target use SCSI
controller chips from the same manufacturer.  In real systems, async
will run between 1.2 and 1.5 MBPS, typical.  Synchronous, on the other
hand, will run 4 MBPS, at any cable length and remain complient to the
specification. 

The > 8 bit SCSI bus is probably a long way off.  I don't think any
current SCSI controllers provide the capability of controlling the
extra data lines.  


Terry Kelleher, Encore Computer
UUCP: {bu-cs,decvax,necntc,talcott}!encore!terryk
Internet: terryk%pinocchio@multimax.ARPA