In computer hardware, a caddy is a container used to hold some medium, such as a

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 data. Computers can read—but not write or erase—CD-ROMs. Some CDs, called enhanced CDs, hold both comp ...

. If the medium is a

hard disk drive A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magn ...

, the caddy is also referred to as a

disk enclosure A disk enclosure is a specialized casing designed to hold and power disk drives while providing a mechanism to allow them to communicate to one or more separate computers. Drive enclosures provide power to the drives therein and convert the dat ...

. Its functionality is similar to that of the 3.5"

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 ...

's jacket. The purpose of a disk caddy is to protect the disk from damage when handling; 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 RCA, in which video and audio could be played back on a TV set using a special stylus and high-density groove system similar to phonograph records. ...

in 1976, and they were used in initial versions of

Blu-ray Disc The Blu-ray Disc (BD), often known simply as Blu-ray, is a digital optical disc data storage format. It was invented and developed in 2005 and released on June 20, 2006 worldwide. It is designed to supersede the DVD format, and capable of stor ...

s, though 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 camcorders ...

discs, or separately attached.

Examples

Caddies date at least to the

, which used a caddy from 1976 to protect the grooves of the disc. While caddies have become obsolete, some websites still sell them, although they have become quite expensive.

Cartridges

In addition to caddies that serve purely a storage purpose, there are also ones that are designed to be loaded directly for data access, usually via a shutter. Some early

drives used a mechanism where CDs had to be inserted into special cartridges, somewhat similar in appearance to a

jewel case Optical disc packaging is the packaging that accompanies CDs, DVDs, and other formats of optical discs. Most packaging is rigid or semi-rigid and designed to protect the media from scratches and other types of exposure damage. 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

s 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 Computer Entertainment. It was first released in Japan on December 12, 2004, in North America on March 24, 2005, and in PAL regions on September 1, 200 ...

, 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, and later, 80 minutes of digitized audio. Sony announced the MiniDisc in September 1992 and released it in November of that year f ...

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. Both 130 mm (5.25 in) and 90 mm (3.5 in) form factors exist. In 1983, just a year after the introduct ...

type disc instead, also in a fixed unopenable caddy.

References

{{reflist Computer storage media