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From: gregl@tekgen.UUCP
Newsgroups: net.micro,net.micro.mac,net.micro.pc,net.micro.att
Subject: Re: SCSI information (was: SCSI pronunciation query)
Message-ID: <108@tekgen.UUCP>
Date: Sat, 24-May-86 15:33:10 EDT
Article-I.D.: tekgen.108
Posted: Sat May 24 15:33:10 1986
Date-Received: Mon, 26-May-86 02:07:10 EDT
References: <703@mtung.UUCP> <3733@sun.uucp> <325@parcvax.Xerox.COM>
Reply-To: gregl@tekgen.UUCP (Greg Lacefield)
Distribution: net
Organization: Tektronix, Inc., Beaverton, OR.
Lines: 42
Keywords: BYTE article SCSI
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If you want to read about the SCSI (Small Computer Systems Interface),
you can find a great article by Steve Ciarcia in the latest (May '86)
BYTE magazine.  It's a two-parter (part two next month), and although
he specifically talks about the NCR 5380 SCSI chip and hooking it onto
his SB180 board, he clues you in on:

	o the background of SCSI (SASI and the ANSI subcommittee)
	o its various system architecture implementation schemes
	o the physical hardware interface
	o the logical interface

Next month, he plans on detailing the communications of the protocol
and the different bus phases.  I recommend this series for those who
have little knowledge of SCSI (like me! :-) .  It's very well written
(like all his articles -- can you tell I'm a fan?).

I've also read up here on the net people saying that SCSI is just SASI
with a name change.  According to Ciarcia, this is true of SCSI _in_its_
_simplest_form_.  To quote:

"SCSI in its simplest form is just a SASI interface.  SASI designs
assume that one host will select a peripheral device, most likely a
disk drive, and remain connected to it until the I/O transfer is
completed.  Because these products are used in low-cost, low-performance
applications, single-ended configurations that do not support parity
are the most popular."
		-- Steve Ciarcia
		   "Adding SCSI to the SB180 Computer
		    Part 1: Introduction"
		   BYTE Magazine, May 1986

Apparently there are more sophisticated SCSI implementations out there
which are NOT the same as SASI (e.g. multi-processor and/or multi-tasking
architectures).  Anybody care to comment?

-----------------------------------------------------------------------
Greg (can you say LAYOFF?  There, I knew you could. :-) Lacefield
...!tektronix!tekgen!gregl
    ^^^^^^^^^ (for now!)

Disclaimer: The above endorsements are my own, not of my employer,
	    whomever THAT might be :-)  <---- pasted smile