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From: jca@pnet01.cts.com (John C. Archambeau)
Newsgroups: comp.sys.ibm.pc.misc
Subject: Re: Mixing hard drive types: ESDI, MFM, IDE
Message-ID: <5569@crash.cts.com>
Date: 10 Nov 90 23:56:01 GMT
Sender: root@crash.cts.com
Organization: People-Net [pnet01], El Cajon CA
Lines: 26

kling@ICS.UCI.EDU (Rob Kling) writes:
>Any comments/explanations about why there might be incompatibilities
>if the appropriate drives are each connected to a proper controller for
>that kind of drive?

Simple, because ESDI, IDE, and ST412/506 use the same port addresses.  An IDE
drive looks to your system like an ST412/506 drive to your system BIOS.

What you could probably do is set your ST412/506 MFM controller card to the
secondary port address, but then you have a problem of setting it to the
second interrupt.  Not to mention that MS-DOS doesn't care to play with second
controllers.

Only big exception is SCSI.  Your SCSI host adaptors are designed to work with
an existing ST412/506, ESDI, or IDE drive already in your system.
 
     // JCA

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