In computer hardware, a caddy is a container used to hold some medium, such as a CD-ROM. 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 magne ...

, 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'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. First ...

in 1976, and they were used in initial versions of Blu-ray Discs, 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 CD-ROM 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, 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 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