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From: dold@mitisft.Convergent.COM (Clarence Dold)
Newsgroups: comp.sys.ibm.pc
Subject: Re: SCSI drive info anyone?
Message-ID: <755@mitisft.Convergent.COM>
Date: 29 Jun 89 16:09:57 GMT
References: <441b1d44.1042a@apollo.COM>
Organization: Convergent Technologies, San Jose, CA
Lines: 21

in article <441b1d44.1042a@apollo.COM>, yon@apollo.COM (David Yon) says:

> 	What I'm curious to know is, how does the AT BIOS know how to inter-
> face to the drive if you have a SCSI port in the way?  Does the BIOS have
> built-in code to recognize that a SCSI port is in the system (which I doubt)
> or does the SCSI port look remarkably like a drive controller board (which I 
> would also doubt).   

There are two answers, in the case of the Unisys 6000/50.

Our BIOS does have special code, to use our controller, as if it were ST506.
MSDOS, and any program using BIOS or DOS access to the disk is unaware that
a SCSI controller is there.  

XENIX, which goes directly to the controller, not using BIOS calls,
won't recognize the SCSI controller without a special driver.
-- 
---
Clarence A Dold - dold@tsmiti.Convergent.COM		(408) 434-5293
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		P.O.Box 6685, San Jose, CA 95150-6685	MS#10-007