Back then, most games filled up all available memory and rarely ever did they have to load from disk, so most games back then were NOT keeping protection in mind. It was a very easy thing to tack on, though, because what would usually happen is the guy in charge of protection would get the game file, then break that up into various pieces himself and write a bootstrap loader that loaded a chunk of game in at a time, then loaded a chunk of loader for the next piece, then executed the loader chunk to load the next piece, etc. Usually they would only have a 256-byte loader (trk 0, sector 0) that would load in the first loader, which was usually the place where they pulled various tricks to hide the loader code.
Sometimes they would load in a piece of code that loaded in at the end of the stack ($100+), over the input buffer ($200+) then when it was done do an RTS which would go to the address that was stored at $1FE-1FF, which ended up being the start of the next loader chunk... It was pretty crazy. I believe Tom McWilliams did most of Sirius' copy protection and he used the little ship graphic from Gorgon while loading the rest of the game.....it definitely made it look like Nasir did the protection himself, but I don't think he did. I could definitely verify this for a fact if you "need to know". BTW, did you know that Ultima II's release was held up because Mark Duchaineau didn't want to protect it with his normal code (he wanted to use his new SpiraTrack scheme) and Sierra was *locked* in to using his protection code.....??? - John > -----Original Message----- > From: Dan Chisarick [mailto:junk6@;bellatlantic.net] > Sent: Monday, November 11, 2002 10:27 PM > To: [EMAIL PROTECTED] > Subject: RE: [SWCollect] [ SWCollect ] What's your favorite find? > > > BTW I have all 89 issues of Computist + the four errata > issues. The Super IOB images are on Asimov. Mail me if > you're interested in any sort of info, etc. I'm not great, > but I've normalized a good stack that weren't in any of those issues. > > John, if you don't mind yet another question your > way... classic game copy protection is one of those perverse > fascinations of mine. Some of them (Nassir's 4+4 encoded, > spiral quarter-tracked, self-modifying > loader-that-sits-on-video-memory with a nibble-count > mess) were just unreal. Mercifully, most schemes were > home-grown almost-DOS 3.3 variants. When writing games that > integrated with copy protection, what considerations did you > have to make? Was development done w/the protection in mind, > or was it normal file-based code until it was ready for > commercial release? > > > -----Original Message----- > From: Edward Franks [mailto:xyzzy@;kc.rr.com] > Sent: Monday, November 11, 2002 2:07 PM > To: [EMAIL PROTECTED] > Subject: Re: [SWCollect] [ SWCollect ] What's your favorite find? > > > > On Sunday, November 10, 2002, at 09:36 PM, C.E. Forman wrote: [Snip] > > I've been thinking about this... and wouldn't it be safer > to play off > > backup copies? I mean, the disk could get munched in the > drive, the > > label could > > get scratched going in and out... or is that attitude too > anal for the > > > rest > > of this group? B-) > > If you can make backup copies. Grrr. Magazines like > The Computist > can be invaluable if you just want to make your legal backups. > > -- > > Edward Franks > <[EMAIL PROTECTED]> > > > ---------------------------------------------------------------------- > This message was sent to you because you are currently > subscribed to the swcollect mailing list. To unsubscribe, > send mail to > [EMAIL PROTECTED] with a subject of 'unsubscribe > swcollect' Archives are available at: > http://www.mail-> [EMAIL PROTECTED]/ > > > > > ---------------------------------------------------------------------- > This message was sent to you because you are currently > subscribed to the swcollect mailing list. To unsubscribe, > send mail to > [EMAIL PROTECTED] with a subject of 'unsubscribe > swcollect' Archives are available at: > http://www.mail-> [EMAIL PROTECTED]/ > ---------------------------------------------------------------------- This message was sent to you because you are currently subscribed to the swcollect mailing list. To unsubscribe, send mail to [EMAIL PROTECTED] with a subject of 'unsubscribe swcollect' Archives are available at: http://www.mail-archive.com/swcollect@;oldskool.org/
