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[[File:Dual format ST and Amiga diskette with Artura and Team Suzuki.jpg|thumb|A dual format games demo diskette.]]

'''Dual format''' is a technique used to allow [[software]] for two systems which would normally require different [[disk format]]s to be recorded on the same [[floppy disk]].

In the late 1980s, the term was used to refer to disks that could be used to boot either an [[Amiga]] or [[Atari ST]] computer. The layout of the first track of the disk was specially laid out to contain an Amiga and an Atari ST [[boot sector]] at the same time by fooling the operating system to think that the track resolved into the format it expected. The technique was used for some commercially available games, and also for the disks [[covermounted]] on [[ST/Amiga Format]] magazine. Other games came on Amiga and [[IBM PC compatible|PC]] dual-format disks, or even "tri-format" disks, which contained the Amiga, Atari ST and PC versions of the game.

Most dual and tri-format disks were implemented using technology developed by Rob {{Not a typo|Northen}} Computing.{{cn|date=August 2022}}

Later, the term was used for disks containing both [[Microsoft Windows|Windows]] and [[Apple Macintosh|Macintosh]] versions.

== Examples ==

<ref>SoftPres News Story [http://www.softpres.org/news:2010-06-08], ''Software Preservation Society'', June 8, 2010, accessed July 26, 2011.</ref><ref>HOL [http://hol.abime.net], ''Amiga Hall of Light'', accessed July 26, 2011.</ref>

:#[[Action Fighter]] (Amiga/PC dual-format disk)
:#[[Lethal Xcess]] - Wings of Death II (Amiga/Atari ST dual-format disks)
:#[[Monster Business]] (Amiga/Atari ST dual-format disk)
:#[[Populous: The Promised Lands]] (Amiga/Atari ST dual-format disk)
:#[[Rick Dangerous]] (Amiga/PC dual-format disk)
:#[[Rick Dangerous 2]] (Amiga/PC dual-format disk)
:#Stone Age (Amiga/Atari ST dual-format disk)
:#[[Street Fighter]] (Amiga/PC dual-format disk)
:#[[StarGlider 2]] (Amiga/Atari ST dual-format disk)
:#[[3D Pool]] (Amiga/Atari ST/PC tri-format disk)
:#[[Stunt Car Racer]] (Amiga/PC dual-format disk)
:#[[Bionic Commando]] (Amiga/PC dual-format disk)
:#[[Carrier Command]] (Amiga/PC dual-format disk)
:#[[Blasteroids]] (Amiga//PC dual-format disk)
:#[[E-Motion]] (Amiga//PC dual-format disk)
:#Indiana Jones and the Last Crusade Action (Amiga//PC dual-format disk)
:#[[Out Run]] (Amiga/PC dual-format disk)
:#[[World Class Leader Board]] (Amiga/PC dual-format disk)
:#[[International Soccer Challenge]] (Amiga/PC dual-format disk)
:#[[MicroProse Soccer]] (Amiga/PC dual-format disk)


== See also ==

{{Portal|Amiga}}

== References==

{{Reflist|30em}}

[[Category:Amiga]]
[[Category:Atari ST]]
[[Category:IBM PC compatibles]]
[[Category:Macintosh platform]]
[[Category:Rotating disc computer storage media]]
[[Category:Software distribution]]
[[Category:Video game distribution]]
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