Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!rutgers!ames!ucbcad!ucbvax!hoptoad!farren
From: farren@hoptoad.uucp (Mike Farren)
Newsgroups: comp.sys.amiga
Subject: Re: SCSI hard disk query
Message-ID: <2084@hoptoad.uucp>
Date: Sat, 2-May-87 04:25:17 EDT
Article-I.D.: hoptoad.2084
Posted: Sat May  2 04:25:17 1987
Date-Received: Sun, 3-May-87 05:37:02 EDT
References: <1730@cbmvax.cbmvax.cbm.UUCP> <78@esunix.UUCP>
Reply-To: farren@hoptoad.UUCP (Mike Farren)
Organization: Nebula Consultants in San Francisco
Lines: 38

In article <78@esunix.UUCP> blgardne@esunix.UUCP (Blaine Gardner) writes:
>  So how about a brief tutorial on how to recognize SCSI vs ST506? If
>I'm looking a "raw" hard drive and it has a 50 pin edge card connector
>it's SCSI, is that what you're saying George? Or are you referring to a
>50 pin DB type connector on an enclosed drive? 

An ST-506 drive has two card edge connectors - one 34 pin (17 on a
side) and one 20 pin (10 on a side).  SCSI drives have one 50 pin - 25
on a side.

>  What kind of connections does a ST506 drive have? And where does SASI
>fit in here? Does ST506 = SASI = IBM PC hard drive?
>
>  I realize that SCSI has lots of potential for huge storage expansion,
>but a lot of Amiga SCSI stuff I've seen seems to be going around in
>circles. What I mean is Amiga -> SCSI then SCSI -> ST506 drive. Why
>waste the hardware (and money!) on SCSI if the drive being used is
>simply the more limited ST506?  Or am I barking up the wrong tree?

First, SCSI more or less equals SASI.  The interface was developed by
Shugart as the Shugart Associates System Interface, and evolved into
the Small Computer System Interface when it was accepted and used by
other companies than Shugart.  The interface is much more general than
the ST-506 interface.  It can accomodate other types of storage
devices than just disk drives, and can allow several devices per
interface without requiring each device to have its own control cable.
Thus, you can put an ST-506 disk drive onto a controller which then
connects to the system via an SCSI interface, and get the cheap price
(and lower performance) of the ST-506 device while retaining one easy
interface.  Not a waste of hardware and money - you can always upgrade
later, and the IBM PC marketplace will take the ST-506 off your
hands...

-- 
----------------
                 "... if the church put in half the time on covetousness
Mike Farren      that it does on lust, this would be a better world ..."
hoptoad!farren       Garrison Keillor, "Lake Wobegbvi		2		2