PackDev Patch document 1.0
			==========================

Introduction
------------

PackDev 1.9 is an excellent and versatile whole-disk-archiving program. It is
available from Aminet, as util/arc/PackDev1_9.lha

PackDev can be used to archive any volume, including floppy disks, MO disks,
and so on. However, there is a bug in version 1.9.


The Bug
-------
PackDev is able to read the bitmap of AmigaDOS-formatted disks to determine
which blocks are used. Unless you specify the ALL keyword, PackDev only
stores the used blocks in the .pkd file it created.

Personally, I *always* use the ALL keyword when archiving disks, since that
preserves all information. For example, there is sometimes interesting data in
the unused blocks; if a file has been deleted but not overwritten, it can be
recovered. Also some games and demos use almost all the disk, but leave the
bitmap unchanged, so PackDev thinks that the disk is almost empty.

Some original disks of mine have an invalid bitmap. These disks have been
write-protected from the day I bought them, and I am not about to write-enable
them to be validated.

It is not possible to determine which blocks are used for an invalidated disk.
Using the ALL keyword it *should* be possible to read all blocks. However,
because of the bug this is not possible.


The Solution
------------
The solution to this problem is to make a copy of your PackDev 1.9 executable
and apply the following simple patch. Use the patched executable for reading
invalidated disks. Use a binary file editor such as Hex to apply it. The offset
and bytes to change are given in hexadecimal.

	Offset		Change From	Change To
	------		-----------	---------
	$000FE2		6506		4E71

With this patch, PackDev will think that all disks use an unknown filesystem,
and therefore will read all blocks regardless of the contents of the source
disk.

The .pkd files created by the patched version of PackDev are compatible with
the original version. You can unpack them back to disks using the original
version of PackDev.

NOTE: If you archive an invalidated disk, and then write the .pkd file back
to a floppy disk, PackDev will force a disk change after writing. This means
that the disk validator will begin to validate the disk. If you want your
written floppy disk to be identical to the original, you must remove it
immediately after PackDev has finished writing it!

You should keep your original PackDev executable and only use the patched
version when you encounter the bug.


Finally
-------
Please let me know if you have any trouble applying the patch.

Please contact me if you know Christian Wasner's email address (he is the
author of PackDev)!


Regards,
-- Mark
mark_k@iname.com