In computer hardware, a caddy is a container used to protect an

optical media An optical disc is a flat, usuallyNon-circular optical discs exist for fashion purposes; see shaped compact disc. disc-shaped object that stores information in the form of physical variations on its surface that can be read with the aid o ...

disc from damage when handling. Its functionality is similar to that of the 3.5"

floppy disk A floppy disk or floppy diskette (casually referred to as a floppy, a diskette, or a disk) is a 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 with a ...

's jacket. Its use dates back to at least the

Capacitance Electronic Disc The Capacitance Electronic Disc (CED) is an analog video disc playback system developed by Radio Corporation of America (RCA), in which video and audio could be played back on a TV set using a special stylus and high-density groove system sim ...

in 1981, and they were also used in initial versions of the

Blu-ray Disc Blu-ray (Blu-ray Disc or BD) is a Digital media, digital optical disc data storage format designed to supersede the DVD format. It was invented and developed in 2005 and released worldwide on June 20, 2006, capable of storing several hours of ...

. As a cost-saving measure, newer versions use hard-coating technology to prevent scratches and do not need a caddy. Caddies may be an integral part of the medium, as in some

DVD-RAM DVD-RAM (DVD Random Access Memory) is a DVD-based disc specification presented in 1996 by the DVD Forum, which specifies rewritable DVD-RAM media and the appropriate DVD writers. DVD-RAM media have been used in computers as well as camcorde ...

discs, or separately attached.

Examples

Caddies date at least to the

, which used a caddy from 1981 to protect the grooves of the disc. Some early

CD-ROM A CD-ROM (, compact disc read-only memory) is a type of read-only memory consisting of a pre-pressed optical compact disc that contains computer data storage, data computers can read, but not write or erase. Some CDs, called enhanced CDs, hold b ...

drives used a mechanism where CDs had to be inserted into special cartridges, somewhat similar in appearance to a jewel case. Although the idea behind this—a tougher plastic shell to protect the disc from damage—was sound, it did not gain wide acceptance among disc manufacturers. Consumers also eschewed the intended and pricey use, which required each disc to be protected with a caddy for its full useful life, preferring to only buy one caddy and transfer the discs between their traditional storage jewel cases and the caddy when in use, then the reverse when finished. Drives that used the caddy format required "bare" discs to be placed into a caddy before use, making them less convenient to use. Drives that worked this way were referred to as ''caddy drives'' or ''caddy load(ing)'', but from about 1994 most computer manufacturers moved to tray-loading, or slot-loading drives. The same system is still available for more recent formats such as

s but is not common. The

PlayStation Portable The PlayStation Portable (PSP) is a handheld game console developed and marketed by Sony Interactive Entertainment, Sony Computer Entertainment. It was first released in Japan on December 12, 2004, in North America on March 24, 2005, and in PA ...

, UMD disc is a similar concept, using a small proprietary DVD-type disc, in a fixed unopenable caddy as both a copy protection and damage prevention measure. The

MiniDisc MiniDisc (MD) is an erasable magneto-optical disc-based data storage format offering a capacity of 60, 74, or 80 minutes of digitized audio. Sony announced the MiniDisc in September 1992 and released it in November of that year for sale i ...

is a similar concept again, using a small proprietary

Magneto-optical A magneto-optical drive is a kind of optical disc drive capable of writing and rewriting data upon a magneto-optical disc. 130 mm (5.25 in) and 90 mm (3.5 in) discs are the most common sizes. In 1983, just a year after t ...

type disc instead, also in a fixed unopenable caddy.

References

{{refs Computer storage media