mort@ihuxn.UUCP (Dubman) (03/04/84)
In response to your request: I know 6502 like the back of my hand, and I am fairly knowledgeable in direct machine language disk access, though I need to brush up a BIT on the "raw data" (prenibbilized) format. There are some really neat protection routines out there, like SPIRALING the data (skipping half-tracks inward every quarter-revolution) and ALL SORTS of insane schemes. Personally, I don't bother to protect the arcade games that I write. I know that with a paperclip, an opened Apple II, and a neat little disk program you can break into just about anything that does not access the disk drive more than once. And for everything else- either Locksmith, Wildcard, or a Boottrace (can work every time) will copy/break it. It depends. If you are trying to just defer the novice from copying your disk, four pokes and a DOS command, and a little program that sticks in a couple of "ninety-sixes" and does a modified COPYA will make a disk that couple of "ninety-sixes" can make your program virtually impossible to crack using normal copy programs. I forget the loca- tion of the D5 AA 96 or whatever hex sequences make up the prolog and the epilog for a data stream but if you change those then COPYA and all those copiers that use RWTS will bomb. -- Jonathan Dubman - care of: Mort Dubman AT&T Bell Laboratories ihnp4!ihuxn!mort Naperville, IL.