Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!ames!sgi!markb@denali.SGI.COM
From: markb@denali.SGI.COM (Mark Bradley)
Newsgroups: comp.arch
Subject: Re: The IPI fast peripheral interface
Summary: IPI vs Sync SCSI
Message-ID: <31965@sgi.SGI.COM>
Date: 3 May 89 18:40:56 GMT
References: <12478@reed.UUCP> <28200303@mcdurb> <648@maxim.ERBE.SE>
Sender: daemon@sgi.SGI.COM
Organization: Silicon Graphics, Inc., Mountain View, CA
Lines: 31

In article <648@maxim.ERBE.SE>, prc@maxim.ERBE.SE (Robert Claeson) writes:
> 
> How well does IPI perform when compared to synchronous SCSI?
> -- 
> Robert Claeson, ERBE DATA AB, P.O. Box 77, S-175 22 Jarfalla, Sweden
> Tel: +46 (0)758-202 50  Fax: +46 (0)758-197 20
> EUnet:   rclaeson@ERBE.SE               uucp:   {uunet,enea}!erbe.se!rclaeson
> ARPAnet: rclaeson%ERBE.SE@uunet.UU.NET  BITNET: rclaeson@ERBE.SE



If you look at specs alone, IPI 2 is faster than synchronous SCSI.
The available devices are faster, too.

IPI level 2 theoretical xfer rate ~12 MB/sec.
Devices announced 2.4-6.0 MB/sec.
This compares favorably with SCSI's 4.0 MB/sec. upper limit.  Unless you
want to go to the cumbersome SCSI 2 hardware, but then where do you get the
drives.  

Then there is striping, arrays, parallel xfer technology, etc.  If you
do things right you can obtain some pretty impressive performance out of
either.

						markb

--
Mark Bradley				"Faster, faster, until the thrill of
IO Subsystems				 speed overcomes the fear of death."
Silicon Graphics Computer Systems
Mountain View, CA			     ---Hunter S. Thompson