Spiradisc (often misspelled as "Spiradisk") was a copy protection scheme used by Sierra On-Line on their

floppy disk A floppy disk or floppy diskette (casually referred to as a floppy, or a diskette) is an obsolescent type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined w ...

releases for the

Apple II The Apple II (stylized as ) is an 8-bit home computer and one of the world's first highly successful mass-produced microcomputer products. It was designed primarily by Steve Wozniak; Jerry Manock developed the design of Apple II's foam-m ...

. The technique, developed by

Mark Duchaineau Mark may refer to: Currency * Bosnia and Herzegovina convertible mark, the currency of Bosnia and Herzegovina * East German mark, the currency of the German Democratic Republic * Estonian mark, the currency of Estonia between 1918 and 1927 * Finn ...

, involved writing the data on spiralling paths on the disk rather than in concentric circles. Initially, no commercial copying software or bit nibbler could successfully copy the disks it was applied to. Games which used Spiradisc copy protection include ''

Lunar Leepers ''Lunar Leeper'', also released as ''Lunar Leepers'', is a horizontally scrolling shooter written by Chuck Bueche and published under Sierra On-Line's SierraVision label in 1982. It was released for the Apple II, Atari 8-bit family, Commodore 64 ...

'', ''

Frogger is a 1981 arcade action game developed by Konami and manufactured by Sega. In North America, it was released by Sega/Gremlin. The object of the game is to direct a series of frogs to their homes by crossing a busy road and a hazardous ri ...

'', some very early versions of ''

Ultima II Ultima may refer to: Places * Ultima, Victoria, a town in Australia * Pangaea Ultima, a supercontinent to occur in the future * ''Ultima'', the larger lobe of the trans-Neptunian object 486958 Arrokoth, nicknamed ''Ultima Thule'' Companies and p ...

'', ''

Jawbreaker Jawbreaker may refer to: * Gobstopper, a hard candy with multiple layers Arts and entertainment * ''Jawbreakers'' (album), an album by Eddie "Lockjaw" Davis and Harry "Sweets" Edison * Jawbreaker (band), an American rock band * Jawbreakers (duo) ...

'',{{cite journal , last1=Etarip , first1=Rich , title=Softkey for ''Jawbreaker'' , journal=

Computist ''Computist'' was a magazine devoted to the Apple II personal computer that was published by Charles R. Haight under the SoftKey Publishing name, between 1981 and 1993, for a total of 89 issues. The magazine was based in Tacoma, Washington. Origi ...

, issue=82 , page
16
, publisher=

SoftKey Publishing SoftKey International (originally SoftKey Software Products, Inc.) was a software company founded by Kevin O'Leary in 1986 in Toronto, Ontario. It was known as The Learning Company from 1995 to 1999 after acquiring The Learning Company and ...

, url=https://archive.org/details/computist-scan-82 , year=1990 ''

Maze Craze Construction Set A maze is a path or collection of paths, typically from an entrance to a goal. The word is used to refer both to branching tour puzzles through which the solver must find a route, and to simpler non-branching ("unicursal") patterns that lea ...

'', and ''

Pest Patrol Pest or The Pest may refer to: Science and medicine * Pest (organism), an animal or plant deemed to be detrimental to humans or human concerns ** Weed, a plant considered undesirable * Infectious disease, an illness resulting from an infection ** ...

''. Eventually, Copy II Plus version 5 was able to successfully defeat this copy protection.

References

External links

COMPUTIST Magazine Articles
by Andy McFadden Sierra Entertainment Copy protection