Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 exptools 1/6/84; site ihuxn.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxl!ihnp4!ihuxn!mort From: mort@ihuxn.UUCP (Dubman) Newsgroups: net.micro.apple Subject: DOS Protection (Re:Josh Siegel) Message-ID: <565@ihuxn.UUCP> Date: Sat, 3-Mar-84 21:28:59 EST Article-I.D.: ihuxn.565 Posted: Sat Mar 3 21:28:59 1984 Date-Received: Mon, 5-Mar-84 00:43:19 EST Organization: AT&T Bell Labs, Naperville, IL Lines: 28 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.