Date   : Mon, 28 Feb 2005 22:03:11 +0000 (GMT)
From   : Greg Cook <debounce@...>
Subject: Re: ADFS OSWord &72 control block byte zero

On 28 Feb 2005 13:40:48 +0000, Jonathan Graham Harston wrote:

> That's a good explanation, except ADFS never sends XY+0 to the
> controller anywhere I can see in the code. I seem to remember
> reading somewhwre that ADFS always uses SCSI controller 1 (or
> zero? - anyway, only one controller).

Might XY+0 be for the unit ID? If Acorn were planning to "do" SCSI
sometime in the future (probable, considering their workstation range),
they may well have allocated a field in the API to select the device in
the SCSI chain.  (Cf. the drive number at XY+0 in OSWORD &7F.)  Does it
get used in the Domesday system?

The other thing is it puts the data address at XY+1 for OSWORD &72 and
&7F, so it might have saved some code when setting up the NMI service
routine.

Greg


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