Double-sided disk
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In computer science, a double-sided disk is a disk of which both sides are used to store data.
Early
Manufacturers sold both single-sided and double-sided disks with the double-sided disks being typically 50% more expensive than single-sided disks. While the magnetic-coated medium was coated on both sides, the single-sided floppies had a read-write notch on only one side, thus allowing only one side of the disk to be used. When users discovered this, they began buying the less-expensive single-sided disks and "notching" them using scissors, a hole punch, or a specially-designed "notcher" to allow them to write to the reverse side of the disk.
Optical discs can also be made in single-sided and double-sided formats, often as an alternative to two-disc packages. Both sides can be either single layered or dual layered or a mixture of both.[3][4] The practice mainly applies to DVDs, but some companies have experimented with pressing discs with differing formats on either side, to varying degrees of success: Universal's first HD-DVD and Blu-Ray releases were double-sided, backed with a DVD version of the movie.[5] DualDisc and DVDplus are two variants of the double-sided DVD format where one side is a compact disc. However, these formats failed due to physical design flaws that impeded their compatibility with many commercial CD players.[6] Specifically, the CD side was either thinner or thicker than a standard CD (whereas the DVD side was thick enough to meet standardized specifications), offsetting it from the focal length of CD players' infrared lasers, and/or causing the discs to have difficulties fitting into slot-loading players and disc changers.
It is more convenient (and cheaper) for videos or music to be released on two single-sided discs. Indeed, many titles that were initially issued as single double-sided discs were later repressed as two single-sided disc sets.
See also
- Floppy disk format - explanation of single-sided double-density
References
- ^ Five decades of disk drive industry firsts, DISK/TREND, publisher of market studies of the worldwide disk drive and data storage industries. web.archive.org
- ^ Sieg, M. G. (March 1981). "Flipping Your Disk". Compute!. p. 71. Retrieved 27 April 2023.
- ^ Prince, Sal. "DVD Size: How Much Data Do the Various Formats Hold?". Lifewire. Retrieved 27 April 2023.
- ^ Halman, Peter; R. Varian, Hal (2000). "Optical Details". How Much Information. Retrieved 27 April 2023.
- ISSN 1059-1028. Retrieved 2023-08-03.
- ^ "DualDisc - The Hybrid CD/DVD Disc. How it was promising..." HighFidelityReview - Hi-Fi systems, DVD-Audio and SACD reviews. 2004-02-12. Retrieved 2023-08-03.