'Fairlight Para-protect'
Author:Lord Crass (guest: search)
Date: Thu, May 12th, 2011 @ 21:00 ( . )

The protection doesn't seem that odd. The drive code is simple: It uses the job queue to load $28/$0e (track 40, sector 14) into the $400 buffer of the drive.

The C64 then reads that buffer to $5200, checks that the byte at $527B is an $83. If it is, then it jumps to the "code" that was loaded at $5200, otherwise it resets the machine.

The problem is that when told to load 40/14, it seems to read in 40/04 instead and returns a disk error 27 (checksum error in header block), so you get garbage in the $400 buffer.

Unless I'm missing something odd about this track, I believe it's a bad dump. It could be that most of the sector headers are bad and in a non-standard order and due to some track sync, it has to land on the correct one (it looks like there's only one sector on this whole track that has any data). I'll look a bit more later.

After the last sector, there's a whole bunch of bad GCR, so this might be throwing off the 1541-II drives.


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'Fairlight Para-protect'
Author:hyper active (registered user: 296 posts )
Date: Fri, May 13th, 2011 @ 02:07 ( . )

I even tried remastering track 40 from several para-protected games but it didn't do any good. Mayhem can you redump the game and attach to an archive and I'll test it out on vice and the real thing?
Thanks.


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'Fairlight Para-protect'
Author:Lord Crass (guest: search)
Date: Fri, May 13th, 2011 @ 20:32 ( . )

Even when you can force it to load the right sector, the data is mostly bad. This sector is corrupted and needs to be re-dumped.

Looking at a few other para-protected games (Galactic Games and Superstar Ice Hockey[PAL]), the on-disk protection is very weak. It relies on you not having a copier that can deal with track 40. These titles even work converted to D64.

The one sector that it does read from track 40 always seems to be sector 14 and does contain data necessary for the program to function (in Galactic Games, the code segment's purpose is to load in the "RECO" file), so this data will differ from game to game. You can't copy a track 40 from one game to another and expect it to work.


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'Fairlight Para-protect'
Author:Lord Crass (guest: search)
Date: Sat, May 14th, 2011 @ 00:27 ( . )

In the database, Starglider is listed as unprotected, but is in fact para-protect V1 (same as Fairlight), while Superstar Ice Hockey(PAL) and Galactic Games are V2.

The alt version of Starglider in the database is a cracked copy that had the track 40 sector relocated to track 35. This was the common method of cracking this protection although track 18 was a more frequent relocation target.


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'Fairlight Para-protect'
Author:hyper active (registered user: 296 posts )
Date: Thu, Jun 23rd, 2011 @ 18:10 ( . )

g'day g'day.
Fairlight has been redumped and is now working, even converted to d64.
Pete I'll send you the nzb image.
Thanks mayhem.


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'Fairlight Para-protect'
Author:hyper active (registered user: 296 posts )
Date: Thu, Jun 23rd, 2011 @ 19:24 ( . )

Um... spoke to soon.
It works on vice, it works on hoxs64, but not remastered.....
Strange.
One of those rare ones that work on some drives and not others perhaps? this is intriguing. Lord crass I'll send you the newly dumped game.


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'Fairlight Para-protect'
Author:hyper active (registered user: 296 posts )
Date: Thu, Jun 23rd, 2011 @ 21:52 ( . )

hmmmmm.
convert it to a g64 and run it on vice and a reset occurs after it tries to read track 40. Try to load the d64 in vice and low and behold it works.
Next, I tried Formatting the disk with a blank 40 track d64, then wrote out the converted fairlight d64 at a speed of 299.59 rpm. Problem solved or so it seems.


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'Fairlight Para-protect'
Author:hyper active (registered user: 296 posts )
Date: Fri, Jun 24th, 2011 @ 03:22 ( . )

Now I think I have it figured out.
After my 1541 drive has been off for a few hours, and I turn it on, and measure the drive speed, it's not exactly 300rpm, it's more like 299.92 rpm.
But the longer I leave it on, the higher the speed goes, if I leave it on for half an hour it will run slightly above 300rpm.
I think this earlier Para-protection relies a lot on drive speed. If it's slightly slower, the odds are the game will die when it attempts to read the signature on track 40.
I left my drive switched off for a few hours and when I turned it back on, the game wouldn't load.
but when I came back after an hour and tried it again, the protection passed and the game started up.
So There's something for you to ponder the next time you have trouble with a para-protected game. Sheesh, they don't call themselves "paranoid software" for nothing.


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'Fairlight Para-protect'
Author:Mayhem (guest: search)
Date: Sat, Jun 25th, 2011 @ 00:06 ( . )

This is the bit that confused me; I converted the NIB of Fairlight to a G64 myself and it loaded perfectly in Vice. Different versions? Or did I get lucky on the attempts? Hmmm, just run it through the last few versions of Vice and all were fine. Odd then...


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'Fairlight Para-protect'
Author:Pete Rittwage (registered user: 558 posts )
Date: Sat, Jul 02nd, 2011 @ 15:01 ( . )

Please send me the redump - I never got it. :)


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'Fairlight Para-protect'
Author:hyper active (registered user: 296 posts )
Date: Sun, Jul 03rd, 2011 @ 20:37 ( . )

check your email


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