'Abacus copy protection'
Author:J Achernar (registered user: 36 posts )
Date: Fri, May 20th, 2011 @ 21:14 ( . )

I believe that the database information for several Abacus titles is incorrect. I have submitted four titles, Cadpak-128, Basic-64, Super-C 64 and Super-C 128. For the last three, the database lists the copy protection as none. Actually, they appear to use some sort of custom loaders.

For the two different versions of Super-C, from a D64 image, they boot into the C environment ok. When any of the three main programs are invoked, CE, E4 and E8, the editor, CC the compiler or CL, the linker, they each first read two blocks (different for each) from t17, move the head to t19, then move the head to the track containing the bulk of the routine (t10 for CC, t15 for CL, t20 for C64 CE and C128 E8, t22 for C128 E4) and hang. They work correctly from a nibbled G64. I haven't tried to dig into the the protection in any detail, but I suspect that they are reading something encoded at the GCR level on t19.

For Basic-64, from a d64, the boot program loads, the head moves to t35 and then the C64 resets. Using a nibbled g64, the main menu is displayed just afer the head moves to t35. I haven't tried to do anything more with Basic-64 yet.


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'Abacus copy protection'
Author:schweppes (registered user: 4 posts )
Date: Thu, Sep 15th, 2011 @ 11:19 ( . )

Concerning BASIC-64: both the Abacus version and the similar version Data Becker sold checked for errors on track 35 (or above).

The original disk bumped the head before it started.

The track indicator in VICE shows that there are 2 or 3 attempts to check something on tracks 35 - 40. A soft reset to $FCE2 is executed if nothing is found.

There is a D64 available somewhere on the 'net which demonstrates this. Of course, the error information is missing ;-)

It is a ZIP file with ~26K, the D64 contains 3 files, CRC32 = c4119c85, probably Abacus version 1.0 as it has fewer files than my German 1.02).

Sorry i can't provide more info on the protection.

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On 05/20/2011 @ 21:14, J Achernar wrote :
I believe that the database information for several Abacus titles is incorrect. I have submitted four titles, Cadpak-128, Basic-64, Super-C 64 and Super-C 128. For the last three, the database lists the copy protection as none. Actually, they appear to use some sort of custom loaders

[.. some text omitted...]
:
: For Basic-64, from a d64, the boot program loads, the head moves to t35 and then the C64 resets. Using a nibbled g64, the main menu is displayed just afer the head moves to t35. I haven't tried to do anything more with Basic-64 yet.
:
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'Abacus copy protection'
Author:schweppes (registered user: 4 posts )
Date: Thu, Sep 15th, 2011 @ 11:46 ( . )

FOUND IT: the protection uses error 21 on track 36!

This one works as expected:

See the [D64[ section of TOSEC and look out for a file named
'Basic 64 Compiler v1.03 (1984)(Data Becker).zip'

If you open the D64 with a BAM editor, the complete track 36 is covered with error 21.

Is it far fetched to guess this was the protection used on ALL Abacus / Data Becker titles of 1984?

Note that the loader in there mentions CADPAK-64 and CHARTPAK-64...


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'Abacus copy protection'
Author:schweppes (registered user: 4 posts )
Date: Thu, Sep 15th, 2011 @ 13:11 ( . )

UPDATE: closer inspection with SC shows the following track / error layout:

Track 36 : No SYNC marks / READ ERROR 21 on S0-16

Track 37-40 : Sector header not found / READ ERROR 20

Simply editing track 36 with Star Commander doesn't do the job - so track 37 and up seems relevant.

Note that cracked versions usually don't have any error info in their D64, but usually check T35-40 right before they start (as can be observed in VICE).
This is at least the case for the 1.0 version floating around (D64 has CRC 5d412d28; probably TOSEC?).


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'Abacus copy protection'
Author:Pete Rittwage (registered user: 558 posts )
Date: Thu, Sep 15th, 2011 @ 14:03 ( . )

I'll double-check it and update the database entry. Thanks very much.


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