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Caddy (hardware)
Encyclopedia
In computer hardware, a caddy refers to a sheath
used to hold some media.
If the medium is a hard disk drive, the caddy is also referred to as a disk enclosure
, which is discussed there. It also refers to optical disks, such as CD-ROM
s, which are the focus of this article.
The purpose of a disk caddy is to protect the disk from damage when handling; their use dates back to at least the Capacitance Electronic Disc in 1976, and they were used in initial versions of Blu-ray Disc
s, though newer versions use hard-coating technology to prevent scratches and do not need a caddy.
Caddies may be an integral part of the media as in some DVD-RAM
discs, or separately attached.
Some early CD-ROM
drives used a mechanism where CDs had to be inserted into special cartridges or caddies, 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. 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 DVD-RAM
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 caddie as both a copy protection and damage prevention measure.
The MiniDisc
is a similar concept again, using a small proprietary Magneto-optical type disc instead, also in a fixed unopenable caddy.
Sheath
Sheath may refer to:* Scabbard, a sheath for holding a sword, knife, or other large blade, as well as guns, such as rifles.* The outer covering of a cable* Condom, a kind of contraception* Debye sheath, a layer of a plasma in physics...
used to hold some media.
If the medium is a hard disk drive, the caddy is also referred to as a disk enclosure
Disk enclosure
A disk enclosure is essentially a specialized chassis 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 data sent across their native data bus into a...
, which is discussed there. It also refers to optical disks, such as CD-ROM
CD-ROM
A CD-ROM is a pre-pressed compact disc that contains data accessible to, but not writable by, a computer for data storage and music playback. The 1985 “Yellow Book” standard developed by Sony and Philips adapted the format to hold any form of binary data....
s, which are the focus of this article.
The purpose of a disk caddy is to protect the disk from damage when handling; their use dates back to at least the Capacitance Electronic Disc in 1976, and they were used in initial versions of Blu-ray Disc
Blu-ray Disc
Blu-ray Disc is an optical disc storage medium designed to supersede the DVD format. The plastic disc is 120 mm in diameter and 1.2 mm thick, the same size as DVDs and CDs. Blu-ray Discs contain 25 GB per layer, with dual layer discs being the norm for feature-length video discs...
s, though newer versions use hard-coating technology to prevent scratches and do not need a caddy.
Caddies may be an integral part of the media as in some DVD-RAM
DVD-RAM
DVD-RAM is a 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 and personal video recorders since 1998.-Design:DVD-RAM is one of three competing...
discs, or separately attached.
Examples
Caddies date at least to the Capacitance Electronic Disc, which used a caddy from 1976 to protect the grooves of the disc.CD-ROM
A CD-ROM is a pre-pressed compact disc that contains data accessible to, but not writable by, a computer for data storage and music playback. The 1985 “Yellow Book” standard developed by Sony and Philips adapted the format to hold any form of binary data....
drives used a mechanism where CDs had to be inserted into special cartridges or caddies, 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. 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 DVD-RAM
DVD-RAM
DVD-RAM is a 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 and personal video recorders since 1998.-Design:DVD-RAM is one of three competing...
s but is not common.
The PlayStation Portable
PlayStation Portable
The is a handheld game console manufactured and marketed by Sony Corporation Development of the console was announced during E3 2003, and it was unveiled on , 2004, at a Sony press conference before E3 2004...
, UMD
Universal Media Disc
The Universal Media Disc is an optical disc medium developed by Sony for use on their PlayStation Portable handheld gaming and multimedia platform...
disc is a similar concept, using a small proprietary DVD-type disc, in a fixed unopenable caddie as both a copy protection and damage prevention measure.
The MiniDisc
MiniDisc
The disc is permanently housed in a cartridge with a sliding door, similar to the casing of a 3.5" floppy disk. This shutter is opened automatically by a mechanism upon insertion. The audio discs can either be recordable or premastered. Recordable MiniDiscs use a magneto-optical system to record...
is a similar concept again, using a small proprietary Magneto-optical type disc instead, also in a fixed unopenable caddy.