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To: Tony Overfield <tony@dell.com>
cc: Terry Lambert <tlambert@primenet.com>, hackers@freebsd.org
Subject: Re: INB question 
In-reply-to: Your message of "Sat, 27 Sep 1997 05:55:43 EST."
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Date: Sun, 28 Sep 1997 18:48:57 +0930
From: Mike Smith <mike@smith.net.au>
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> At 02:44 PM 9/19/97 +0000, Terry Lambert wrote:
> >> > Yeah;  that's why I picked the extended MCA DMA ports for the detect;
> >> > that, and I can do the probe non-destructively, with the expectation of
> >> > a 0 bit in my data and no hardware configuratio changes resulting.
> >> 
> >> Where is the port exactly?  ie. is it likely to be sat on or masked 
> >> over by an ISA device?
> >
> >Port 0x18 is the control, and port 0x1A is the data.
> 
> Port 0x18, on many systems, is an alias of port 0x08, which is 
> the read-only DMA status register and the write-only DMA command 
> register.  Likewise, port 0x1A is often an alias of the write-only 
> port 0x0A DMA mask register.

Eep.  That's not so good then.  Now you're back; do *you* know how to 
identify an MCA machine uniquely?

mike