Thomas Jentzsch Posted November 21, 2001 Share Posted November 21, 2001 I just discovered that there exists a game (Steeplechase from VideoGems) that is protected against hacks. Does anybody know any more games or the story behind this one? (Anti-Pirating?) Quote Link to comment Share on other sites More sharing options...
Scott Stilphen Posted November 21, 2001 Share Posted November 21, 2001 Does it use a checksum for the graphics? Quote Link to comment Share on other sites More sharing options...
Thomas Jentzsch Posted November 21, 2001 Author Share Posted November 21, 2001 quote: Originally posted by Scott Stilphen: Does it use a checksum for the graphics? Not only the graphics, but for the complete ROM. Quote Link to comment Share on other sites More sharing options...
Albert Posted November 21, 2001 Share Posted November 21, 2001 I don't know very much (yet) about 2600 programming, but couldn't this game be easily disassembled with Distella to remove this crude copy protection? ..Al Quote Link to comment Share on other sites More sharing options...
Thomas Jentzsch Posted November 21, 2001 Author Share Posted November 21, 2001 quote: Originally posted by Russ Perry Jr: How much of the codespace is wasted to do the anti-hack protection? The protection algorithm is very simple (just adding all the bytes) and the code is very short too (less than 40 bytes). So, I won't remove the protection code, and just patch one byte, so the checksum will be correct again. Quote Link to comment Share on other sites More sharing options...
slapdash Posted November 22, 2001 Share Posted November 22, 2001 How much of the codespace is wasted to do the anti-hack protection? Quote Link to comment Share on other sites More sharing options...
Thomas Jentzsch Posted November 22, 2001 Author Share Posted November 22, 2001 Update The new two Video Gems ROMs (Mission Survive and Treasure Below) have the same checksum code inside. I'm starting to wonder, if this was done to prevent pirates from hacking the game or just to have a simple way to check the integrity of a cart. Quote Link to comment Share on other sites More sharing options...
cschell Posted November 22, 2001 Share Posted November 22, 2001 quote: Originally posted by Thomas Jentzsch: I'm starting to wonder, if this was done to prevent pirates from hacking the game or just to have a simple way to check the integrity of a cart. Does the game have a copyright display that would make pirates want to alter the game? And what does it do if it fails the checksum? Does it sit there with a black screen or corrupted display, or possibly put up a red or orange screen? If it has a copyright display, and just shows a black or corrupted display, it's probably to thwart pirates. If it puts up a red or orange display it's quite likely the error check - as red is often used as a warning that something is wrong. The Supercharger, for example, displays an orange screen if any of it's RAM banks fails an initial start up test. Chad Quote Link to comment Share on other sites More sharing options...
Thomas Jentzsch Posted November 22, 2001 Author Share Posted November 22, 2001 quote: Originally posted by C. Schell: Does the game have a copyright display that would make pirates want to alter the game? Yes, they display a Video Gems copyright notice. quote: And what does it do if it fails the checksum? Does it sit there with a black screen or corrupted display, or possibly put up a red or orange screen? It differs. Steeple Chase, Mission Survive, Surfer's Paradise and Missile Control produce a buzzy noise and go into an infinite loop. Treasure Below only set's the volume high and then breaks, which makes the cart restart again. All show no display at all. BTW: There was a thread here (or Atari Nexus) some months ago, where they discussed an error of a multicart (X in 1), where one game would fail if you played another before, due to a carry flag state. Thought it might be useful for you to know about. Quote Link to comment Share on other sites More sharing options...
Scott Stilphen Posted November 22, 2001 Share Posted November 22, 2001 It sounds like an anti-piracy measure. I doubt VG would bother to incorporate a 'cart integrety' check - if something is wrong with the chip (they're all 4K, right?), it'll be pretty obvious Unlike the Supercharger, which you could possibly repair. Guess this makes VG the first to use 'security' code in games. Quote Link to comment Share on other sites More sharing options...
Thomas Jentzsch Posted November 22, 2001 Author Share Posted November 22, 2001 quote: Originally posted by Scott Stilphen: It sounds like an anti-piracy measure. I doubt VG would bother to incorporate a 'cart integrety' check - if something is wrong with the chip (they're all 4K, right?), it'll be pretty obvious That way you could find out, if some bits got corrupted by simply plugging the cart into the console. Else, you had to playtest each cart. But there should have been other hardware tools available that verify the integrity of a cart. How is it done today? quote: Guess this makes VG the first to use 'security' code in games. I'm still not convinced, because the code is so dead simple. It just patched Steeple Chase from PAL into NTSC without removing the protection code. Maybe it was more difficult to find it during the early 80s. It would be nice to know, what tools the pirates used. Or to get in contact with a programmer from Video Gems. Quote Link to comment Share on other sites More sharing options...
Scott Stilphen Posted November 22, 2001 Share Posted November 22, 2001 quote: Originally posted by Thomas Jentzsch: That way you could find out, if some bits got corrupted by simply plugging the cart into the console. Else, you had to playtest each cart. Honestly, what are the odds of that happening? Next to nil, if they used ROMS (I could see if they used EPROMS, like some companies). I've never come across that problem, or heard about it (and some of the original releases are nearly 25 years old now). The only bad carts I've seen are completely bad (infamous VCS 'striped death' screen) [ 11-22-2001: Message edited by: Scott Stilphen ] Quote Link to comment Share on other sites More sharing options...
Albert Posted November 22, 2001 Share Posted November 22, 2001 I have a hard time believing that Video Gems put this routine in their games as a cart integrity check. I mean, how often do carts actually fail? Given the rampant piracy in some parts of the world, I feel it much more likely that this was done in an attempt to thwart people who might easily pirate their games. Granted, it doesn't take much to bypass this protection, but it will prevent someone from just simpliy changing the graphics to produce a "new" title (which is all many pirate carts did!) We take for granted all the tools we have today to dump, disassemble, compile, play, and create 2600 carts. Certainly this was considerably more difficult and expensive back in the early 80s. If it was easier to pirate Company A's carts that had no protection, versus Company B's games that had some protection, you can imagine what most pirate companies would do. ..Al Quote Link to comment Share on other sites More sharing options...
Thomas Jentzsch Posted November 22, 2001 Author Share Posted November 22, 2001 quote: Originally posted by Scott Stilphen: Honestly, what are the odds of that happening? Next to nil, if they used ROMS (I could see if they used EPROMS, like some companies). You guys know much more about the related hardware and the situation in the 80s, so I think, I have to agree. Ok, that makes me the first guy of the millenium, who (re)discovered a pirate-protected Atari 2600 game. Quote Link to comment Share on other sites More sharing options...
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