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From: jca@pnet01.cts.com (John C. Archambeau)
Newsgroups: comp.sys.ibm.pc
Subject: Re: INFO needed for MFM, SCSI, IDE drive
Message-ID: <2575@crash.cts.com>
Date: 8 May 90 05:36:08 GMT
Sender: root@crash.cts.com
Organization: People-Net [pnet01], El Cajon CA
Lines: 50

khioe@mona.Jpl.Nasa.Gov (Kent Hioe) writes:
>
>1. Does any one know if we can install SCSI disk drive with MFM controller
>   (WD1006V) ?
 
Yes.  The actual nuts and bolts of doing it varies greatly from manufacturer
to manufacturer, but it can be done.

>2. Can we install MFM (controller + disk drive) as drive 1 and 
>   SCSI (controller + disk drive) as drive 2 on the same machine 
>   (386) ? 
 
Drive 2 meaning the drive 2 in your BIOS?  If that's the case, no.  The reason
being that SCSI is not supported in any motherboard BIOS chip (only exception
are those odd ball motherboards that have an on-board SCSI port, and there are
a few of them).  The SCSI host adaptor will have its own on-board BIOS and how
the logical drives are mapped varies greatly from manufacturer to
manufacturer.

>3. Can we install MFM (controller + disk drive) as drive 1 and 
>   IDE (controller + disk drive) as drive 2 on the same machine (386) ?

No.  The specifications for IDE (according to the Seagate IDE installation
guide) calls for either an ST412/506 or an IDE in your machine, but NEVER
both.  You choose one or the other.  Now I have been thinking since an IDE
generally appears to be a WD1006V-MM1 to the BIOS, what if I hang a
WD1006V-MM1 in my machine, but at the secondary port addresses?  Would that
work?  That I don't know yet.  I may call Western Digital and ask one of there
application engineers if that will work.  I also called ALR about using an IDE
and a WD1006V-MM1 with Novell Netware (this was back in the days when I was
totally ignorant of what the hell IDE was)...and it's a no no.  The spec for
IDE calls for either an ST412/506 or an IDE installed in your machine, NEVER
both.  But I am thinking if I can get around it with the secondary port
setting on the ST412/506 controller which may just work.

If my crazy idea will work, then you need an OS that will talk to the
controller at the secondary port address.  I know Xenix will do it, but you
have to make sure that both controllers are running off int 15 which usually
means soldering a lead to the int 15 connection on your motherboard.
 
     // JCA

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