The CYAN loader

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SLC
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The CYAN loader

Post by SLC » Mon Feb 27, 2017 1:05 pm

I've just been in touch with someone who claims he wrote this loader, and if we're talking about the same loader it's also used on Who Dares Wins II from Alligata. Is anyone able to confirm that this one has the early CYAN loader? If it is, the real name of this loader is apparently Promat 64, and was written by David Partington who worked at US Gold from 1986-1989. David also wrote the Pro Cass tape mastering system which replaced Novaload for tape games.

The descriptions David himself provided me does match very well with the description I can find on c64preservation.com. For your amusement I will post that section of the e-mail below:
I can help you with the disk protection using Track 40 since I wrote it :) That is Promat 64, something I developed in 1984/5 prior to joining US Gold. It's also used on many other companies titles both before I joined US Gold and after I left. The very first one to use it (if I remember correctly) was "Who Dares Wins 2", plus 3 or 4 other titles by the same company (can't remember the name of the company!)

The system uses "block execute" commands in the drive to check the protection (I seem to remember track 15/16/17 - but it's a long time ago and I'm sure the archivists know more accurately) and then either return the 'good' code that then loads the game or returns a different (bad) block of code that wipes memory, so the copy protection was checked in the drive, not the C64.

If you're not sure what block executes were (sorry, I'm not sure how deep you go in the drive) it's a way of telling the drive to load a disk sector (block) in to internal memory and then execute that memory as code using it's own 6502 CPU. Quite handy since not many people knew about it. The only "gotcha" was that a third party started making Commodore compatible drives but for some unknown own reason the only thing they didn't duplicate was the block execute command, hence no titles using Promat 64 would load on them.

The system placed a single file on the disk (3K I think) that is lightly encrypted using self modifying code that then calls the block execute stuff. There is an easy back door if you know where to look :) I recall our marketing manager storming in to my office and throwing a magazine article in front of me about a game being hacked and how to do it. It was a helicopter game from 1988(?), 'Thunder' something (can't remember). Anyway, red faced I began reading the article waiting to find out how they did it so I could modify the system to avoid it, only to find at the end of these two pages that the hacker gave up because he couldn't find any more files on the disk! The fact is our loader never needed files in the disk directory because the only thing the directory did for you was tell you where the file started. Well, we already knew where the files started because we'd put them there, so we just passed the start block to the loader and bypassed the directory altogether :)
I do not have these games myself so I cannot check if it's really the same loader, but as I said, it seems very likely on comparing what c64preservation says about it and what David mentions himself. Hope it was an interesting read regardless. :)

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IFW
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Re: The CYAN loader

Post by IFW » Mon Feb 27, 2017 2:57 pm

Yes, it could be - though not sure about Who Dares Wins II, as far as I remember dumps we have so far are from the OziSoft version, and those always use a custom disk format and good encryption and were only released in Australia.
The company is Alligata Software.

SLC
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Re: The CYAN loader

Post by SLC » Mon Feb 27, 2017 3:41 pm

I also checked c64preservation for titles including "Thunder" and that seemed to be a helicopter game, and Thunderblade does indeed seem to contain the "CYAN"-loader. So this loader might be Promat 64 as David suggests, then. :)

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Mayhem
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Re: The CYAN loader

Post by Mayhem » Mon Feb 27, 2017 5:26 pm

As soon as he said "Thunder", then I knew it was probably "Thunder Blade" because US Gold released the conversion of it (programmed by Chris Butler).
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Hok of Remember
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Re: The CYAN loader

Post by Hok of Remember » Tue Feb 28, 2017 9:04 am

Very nice read and good information there, thanks, SLC!
Yes, it could be - though not sure about Who Dares Wins II, as far as I remember dumps we have so far are from the OziSoft version, and those always use a custom disk format and good encryption and were only released in Australia.
The company is Alligata Software.
We also got a good dump (not profesionally duplicated, but probably unmodified) of the original Alligata-release of the game which I did on 2015-09-17 (game is extremely rare, it used to be in Sebastian K.'s collection, now it is in mine). Just by looking at what the disk drive does upon booting the image in Vice, this could very well be protected by a predecessor of the Cyan-protection.
Once upon a time

rcade
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Re: The CYAN loader

Post by rcade » Fri Mar 03, 2017 3:50 am

Could be... the description is vague enough to be anything. I don't have dumps of WDW or WDW2 either...
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Pete Rittwage
C64 Preservation Project
http://c64preservation.com

SLC
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Re: The CYAN loader

Post by SLC » Fri Mar 03, 2017 1:14 pm

I have since talked to Jani who did some more extensive research on the loader, and all the details given is actually lining up with all the info I got from David, and the fact that Thunder Blade is mentioned, and also is confirmed using that loader, there's no doubt in my mind, at least :)

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