Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!ucla-cs!ucivax!jarthur!uunet!xstor!bang!iverson
From: iverson@bang.uucp (Tim Iverson)
Newsgroups: comp.periphs.scsi
Subject: Re: Mixing SCSI and Other Drive Types
Summary: it's easy
Message-ID: <1991Feb08.080113.79@bang.uucp>
Date: 8 Feb 91 08:01:13 GMT
References: <1991Feb5.184829.11025@pwa-b.uucp>
Reply-To: iverson@xstor.com
Followup-To: comp.periphs.scsi
Distribution: usa
Organization: House of the Smoking Gun
Lines: 28

In article <1991Feb5.184829.11025@pwa-b.uucp> merusi@pwa-b.uucp (Don Merusi) writes:
>Is it possible to mix MFM, RLL and SCSI drives together on the same
>system. I would be interested in learning what the legal combination are.

If I can assume you're talking about PC-clones here, then I can say that
one of nicest things about SCSI for PCs is that it mixes with *everything*.
Almost all MFM,RLL,&ESDI are just wd1003 register-set controllers; almost
all SCSI host-adapters are not 1003 compatible.  So, since they don't
fight, they live together in perfect harmony (grain of salt not included).

If you're talking about DOS here, a dumb SCSI card will give you better
performance at a lower price than one of the smarter "bus-mastering" cards -
especially if you're using windows or desqview.  If you need Unix of any
flavor, you will not be able to live without an Adaptec 1542 (or Bustek 540
- a faster adaptec clone).  This card performs very well under Unix, is
moderately priced, and all major PC-unixes support it out of the box.

>SOme people are telling me you can only mix MFM and SCSI, and not
>SCSI and RLL. If the SCSI is installed on a separate card does it make
>a difference?

I don't know of any cards that have both a 1003 style controller and a SCSI
host adapter.  You should probably plan on adding one host adapter card for
every 7 scsi devices you install.


- Tim Iverson
  iverson@xstor.com -/- uunet!xstor!iverson