Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!uunet!tut.cis.ohio-state.edu!pt.cs.cmu.edu!andrew.cmu.edu!gt0t+ From: gt0t+@andrew.cmu.edu (Gregory Ross Thompson) Newsgroups: comp.sys.apple2 Subject: Re: Spiral-tracking Message-ID: Date: 13 Apr 90 00:06:35 GMT References: <1544@polari.UUCP> Distribution: na Organization: Carnegie Mellon, Pittsburgh, PA Lines: 21 In-Reply-To: <1544@polari.UUCP> tm@polari.UUCP (Toshi Morita) writes: > If I remember correctly, Br0derbund's spiral tracking (a la Choplifter) used > adjacent half-tracks in concentric half-circles to achieve one of the most > difficult copy-protechtion schemes ever, (not quarter tracks). The spiral tracking protection method was called Spiradisk, and invented by a guy named Mark Duchaineau. It loaded about 20 times faster than DOS 3.3 did. There were two main problems with it. The first was that it took up about half of the disk. The other was that the disks often had to be rebooted once or twice before the program would load. It was first used on some of Sierra On-Line's software. > Nice to see all the slick programmers (kadickey, nicholas) on Usenet! Yeah, it sure is... > Toshi Morita > ..!uunet!microsoft!uw-beaver!sumax!polari!tm -Greg T.