"Market" for old macs?
bfranchuk at jetnet.ab.ca
Fri Dec 2 18:18:14 CST 2005
Jim Leonard wrote:
> Chuck Guzis wrote:
>> games were infamous for it. Oddly, many copy protection schemes
>> could be
>> defeated by simply patching the code to dummy up the subroutine that
>> reported that the copy protection was intact.
> Replace "many" with "some" and I'd agree. There were some schemes
> that were simply evil in their cleverness and ingenuity. King's Quest
> 2 encrypted the main code with a cypher kept somewhere abnormal (like
> a 10th sector or 41st track, can't remember the exact one) that was
> transparently missed by DISKCOPY: you could make a copy without
> errors, but it wouldn't work... and the decryption routine was itself
> obfuscated with some clever self-modifying code, so you couldn't just
> dump the raw code and (U)nassemble it -- in fact, you couldn't do THAT
> EITHER because the game was a bootable program with it's own disk
> routines. Took three weeks to unravel that monster, starting with the
> only code you *could* look at: the 512-byte boot sector.
> By far the worst was another bootable game (Dunzhin: Warriors of Ras)
> that didn't use INT 13h BIOS services to read diskette sectors, but
> rather raw NEC FDC commands. Int 13h is easy to work with; raw NEC
> commands are not, and I'm no Guzis or Dunfield :-)
> But I agree with you that some DOS-based games were so trivial that
> they could be cracked with a hex editor and not a debugger. For
> example, replace INT 13h disk call opcodes (CD13) with NOP opcodes
> (9090) and the program would just "fall through" the protection
> routine... or finding a list of null-terminated manual code words and
> changing them to ALL nuls and then you could merely hit Enter at the
> password request.
> I'm giving away too much information about myself, aren't I? :-)
> The future of software protection is coming, and it's not pretty.
> Public-key assymetric encryption schemes are already in use; your
> software phones the mothership to authenticate. Joy.
Good reading but most games I'd buy rather than pirate. I will pirate
out of print games, cause how else can you
get them. Now the real grey area in games is now pirated but fan
subtiltled or translated games from the Land of Japan.
Alot of interesting tiles but not mass market stuff in the USA. I don't
worry , I got a analog phone. :)
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