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Re: Need replacement disks for Tower of Myraglen

Mitchell Spector wrote:

"Michael J. Mahon" <mjmahon@aol.com> wrote:



Mitchell Spector wrote:


Just got an interesting gift tonight. One of my friends was at a
flea market and picked me up an original copy (apparently never
used!) of PBI's Tower of Myraglen game. Everything came in near
mint condition, although it seems after some 20 years the floppy
disks experienced disk rot. :(

  I can see a listing of the files from the Finder but it fails to boot
(and doing a verification of the disk reveals +90% is unreadable
with errors; the second disk faired a bit better though).


You might want to try some ProDOS-based tools to see if you can
recover the contents,



    Ah, did have some luck copying most files off from the Finder!
The generic ProDOS 16 files are corrupt (boot stub and System
folder) as well as two game files named "TITLESCREEN3" and
"THUNDERSOUND". No problem, I have good copies on the pirated copy, so I mixed them altogether on a fresh disk... 

Good approach!


though if it is protected, it's not likely
that you can do this without patching RWTS.
When booting the new disk, I get a message saying "You must BOOT from master!". So it is copy-protected.
Looks like either the system files or the boot sectors are corrupt, with most of the actual game files intact. I could take a gamble and 
try copying over just those files though chances are I'll get an I/O
error trying to copy over them.


I haven't looked at this title, but it is possible that it uses a
"designed" error block or blocks as a signature for the "master" disk.

If this is the case, then you will need to either use a low-level
nibble copy program to create the block errors it checks for, or
find the checking routine and disable it.

The second approach is clearly better, since it moves the disk
closer (maybe all the way) to deprotected status.

Since it prints out the message, you can use a block editor to search
the disk for that string, then examine code in the vicinity to see
what is printing it.  Patch that so that it enters the monitor instead
of printing, and examine the stack to see where it was called from,
and proceed back in this way until you find the "verification" code,
then disable it.


It's normal for a protected disk not to verify.



    Yep, that would explain all the holes/errors when trying to image
or duplicate the disk.



Does the disk boot properly?



    Not at all. Either I get an "UNABLE TO LOAD PRODOS" message
or I/O error. I did once get a ProDOS 16 splash screen before crashing
into Monitor. 

So the disk is getting some errors, but they are not "hard" errors...


     Interestingly, the more I access the disk, the more data it's starting
to read. Now I'm seeing "Error reading SYSTEM/P16 file $000F" and
if I launch from the Finder, it gives me the copy-protection failure message about booting from the master disk. Hmm. 

It sounds like this disk will be almost completely recoverable, at least
when supplemented with the files/data from the cracked version.

The fact that you get the "master disk" error so early is also
encouraging, since it may just be an single check early in the
game loading process.  It is more difficult if the game re-checks
the disk multiple times throughout the game.  The same check
removal principles apply, but there is always a question about
whether *all* the checks have been found and disabled.


   I need a clean copy from an original disk set (I'd be happy to scan
the manual and disks if anyone wants proof that I own the original).
I tried doing an image copy of the original disk with ZZCopy but it
shows the disk completely full of "holes". Amusing that the pirated version has out lived the legal copy. :) 

In general, you won't be able to make a good image copy of a
protected disk--that's why deprotecting them is preferred.



    There's actually a bitcopy parameter for the game in Copy II Plus 9.1
but it didn't seem to help using it to copy the disk.


It wasn't unusual for games to use more than one method over their
production lives.  Copy parameters were a kind of cat and mouse game
that often resulted in out of date published parameters.

Because Computist was a lower-circulation publication, it usually
had the more complete story on how to deprotect a program.


Have you tried a different drive?  (I presume this is a 3.5" disk.)



    Yes, it's an 800K 3.5 floppy. I tried it in both my Apple 3.5 and
SuperDrive.


If you want to do anything low-level (like a Copy II Plus bit copy),
you'll have to use your 800K floppy *without* the superdrive controller.
The superdrive controller card does not provide low-level (nibble)
access.


Another possibility is to replace the crack screen with the original
intro screen (if it's readable).

Of course, both strategies require doing a fair amount of the
deprotection work, but that was usually more fun than the game.  ;-)



    Won't do, when it was deprotected they removed some of the
graphic files (the ones with credits and copyrights) and added a set of new files and sound effects. 

With any luck, you can recover those from the original disk.

-michael

New, faster SUDOKU v2.0 solver for Apple II's!
Home page:  http://members.aol.com/MJMahon/

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