A shaped Compact Disc is a non-circular compact disc. Examples include business card CDs, CDs in the shape of a star, a map of a country, and more. These disks are usually made for marketing purposes and are properly read by most CD-ROM drives (and audio CD players, although custom-shaped CDs tend to contain less data). There are many companies that sell CDs with custom shapes.
Unlike Mini CDs, which are smaller, but still circular versions of normal CDs, custom CDs can be any number of shapes, even more complicated shapes like gears with dozens of teeth, but are generally smooth and with rounded edges, such as ovals or rounded rectangles. A logo can be printed on a shaped CD, in the same way common audio CDs and CD-ROMs are labeled.
Shaped CDs are produced in one of two ways. A special mold can be made and used to "stamp" CDs (or DVDs) as part of the precision injection molding process that is used to make CDs and DVDs. Because of the initial cost involved in setting up this process, it is usually used for mass production. For the same reason, this is generally restricted to the production of read only CDs and DVDs (CD-rom or DVD-rom). Recordable CDs and DVDs (CD-r or DVD-r or DVD+r) are not generally available except in standard shapes including rectangular. The second method to produce a shaped CD or DVD is to produce a normal CD-rom or DVD-rom and cut it to the desired shape. This method works only for CD-rom. It will not work for CD-r because the plastic used to produce CD-r tends to splinter when cut. It is important that two criteria be met for shaped disk to function properly. First, the shape must be balanced to avoid problems when it begins to spin. Second at least three points of the outer edge must touch either the outer 12 cm diameter rim of the players tray where standard size discs fit or the inner rim where 8 cm diameter mini discs fit.
Data can only be recorded on sections of a Shaped CD that form uninterrupted circular tracks. Other parts of the shape are purely decorative - but are still often finished to the same appearance as a CD. They appear silver and reflective on the data side of the CD, even though they contain no actual valid bytes and cannot be read.
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