Date   : Tue, 29 Apr 2003 09:35:46 +0100
From   : Richard_Talbot-Watkins@...
Subject: Re: BBC Micro Games Copy Protection

John Kortink <kortink@...> wrote:

> I can remember what a nightmare the tape version of Elite was.
> It used every trick in the book, fake tape blocks, interrupt
> routines, tricky timing, garbled routines, jumping all over
> the place, using almost every free byte in the machine. I did
> manage to hack it (still have the hacked version). I later
> bought the disc version as well though.

The original Acornsoft disc version of Elite didn't run on a Master.  It
didn't even get as far as the "Saturn made out of dots" screen; instead it
just thrashed the disc drive head repeatedly in a rather alarming way.  I
assume its protection methods were not Master compatible for some reason.
Does anyone know why?  It was one of the first games I had, and back then I
didn't know enough to be able to go about fixing it.  In the end, I
part-exchanged it for the Superior/Acornsoft disc version with the Master
version included, so was never able to investigate what was up with it
later on.

Getting old games running on my Master became another reason to have to
hack into their innards.  The usual things which screwed up on a Master
were OS1.20 only calls (all Ultimate games, Wizadore, Boffin, Way of the
Exploding Fist and many others), undocumented 6502 instructions (Zalaga,
Repton), plotting characters directly from the character set stored at
&C000-&C2F7 in OS1.20 (all Ultimate games - again), referencing the screen
row lookup table in OS1.20 (Castle Quest, Frak) and poking UDG definitions
straight into &C00-&CFF (loads of stuff was guilty of this).  It was a
great way of learning things about the Beeb though.  I never did quite get
Frak working ok... I found knives and stuff appearing and disappearing
randomly.  And as for Alien8.... grrrrrr.....

Rich
--
                                                                           
 Rich Talbot-Watkins                       Richard_Talbot-Watkins@...      
 Sony Computer Entertainment Europe              Direct line: 01223 341865 
 Cambridge Studio                                                          
                                                                           






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