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From: billkatt@sol.engin.umich.edu (Steve Bollinger)
Newsgroups: comp.periphs,comp.sys.mac
Subject: Re: SCSI interfaces
Message-ID: <4115d90b.a590@mag.engin.umich.edu>
Date: 26 Jan 89 01:27:00 GMT
References: <1138@naucse.UUCP>
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Reply-To: billkatt@caen.engin.umich.edu (Steve Bollinger)
Organization: Computer Aided Engineering Network (CAEN), University of Michigan
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In article <1138@naucse.UUCP> rrw@naucse.UUCP (Robert Wier) writes:
>
> We are looking for information on how compatible are devices designed
> for SCSI, *really*?  For example, could you buy a HD being marketed
> for the Macintosh, and use it on an HP workstation which has a
> SCSI port?  I have heard (I can't remember where exactly), that 
> Apple's use of the SCSI is somewhat non-conforming to the standard.
> Is this true?  How about other devices?  Is everyone else compatible?

There are really two ways in which the mac is non-standard.  First, they only
use a 25-pin connector.  This is not an issue because the 25 pins they
omitted are all grounds, and most SCSI cables just split the ground which is
available out to 26 different lines.  There is no standard connector for SCSI,
Apple uses a centronics type (except on the back of the Plus, SE, and I
series), and Sun uses a D-shell connector.  The other way that Apple is
non-standard is that it requires a driver for its SCSI drives.  This is good
because that way both standard and non-standard drives can be supported,
however, I would rather that they used direct SCSI calls and required standard
drives.  The important factor is that with the correct cable and driver, you
can use any standard (and many non-standard) SCSI drive on a Mac.  On the
other hand, we have a Maxtor drive which works on a Mac but not a Sun.

I repeat: any drive which works on a NeXT or a Sun will work on a Mac, so stop
yer gripin' B-)


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