Subject: Re: 5.25 drive-icon patch for System 6.0.1
From: [email-masked] (David Empson)
Date: 26 Apr 1996 02:01:10 +1200
Newsgroups: comp.sys.apple2

In article <[email-masked]>,
Mitchell Spector <[email-masked]> wrote:
> 	A while back I re-installed System 6.0.1, but in doing so at
> the time, it replaced my patched 'Apple5.25' driver. The patch was no
> more than a changed auxilary filetype so that only one 5.25 drive 
> icon appears on the desktop rather than two. Unfortunately I cannot
> remember what that was, so can someone refresh my memory? :)
> 
> Current aux-type = $010E, new aux-type = $????	

$0101.  For a standard GS/OS device driver, the lower six bits specify
the number of devices supported by the driver (see the file type note
on GS/OS drivers: FTN.BB.XXXX), so the maximum number of devices that
can be supported by a single driver is 63.  You should NEVER increase
this higher than the original value, because the driver probably
doesn't have space in its device tables to support more drivers than
it originally claimed to.

The AppleDisk5.25 driver supports a maximum of 14 devices - two 5.25"
drives for each available slot.  (In theory, it should be able to
support 16: all seven real slots, plus the built-in disk port, but
Apple never completed the implementation of dynamic slot switching for
drivers, probably for compatibility reasons.)

Don't change any of the higher order bits.  The high order byte
specifies the type of driver ($01 = GS/OS device driver), and the top
two bits of the low order byte specify the type of GS/OS driver (00 =
standard).

NOTE: All of the above applies ONLY to GS/OS standard device drivers,
not to GS/OS supervisory drivers, printer drivers, or anything else.
See the filetype note for further information.

There is one bit in the auxiliary type which is the same for all types
of drivers: bit 15 set ($8000) indicates the driver is inactive (this
is what Finder toggles when you click on the "Inactive" check box).
-- 
David Empson
[email-masked]
Snail mail: P.O. Box 27-103, Wellington, New Zealand