optical disk

[′äp·tə·kəl ′disk]

(computer science)

A type of video disk storage device consisting of a pressed disk with a spiral groove at the bottom of which are submicrometer-sized depressions that are sensed by a laser beam.

optical disc

A direct access storage device that is written and read by light. The most common types are CD, DVD and Blu-ray. As removable media, optical discs superseded the earlier magnetic disk cartridges because they weigh less, have higher capacities and are not subject to head crashes or corruption from stray magnetic fields. Optical media also have a 30-year life and are less vulnerable to extreme hot or cold.

However, as a transportable storage medium, they have mostly been superseded by USB-based flash drives and external hard drives. Following are the major categories of optical discs in order of writability.

Read-Only (Factory Pressed)
Read-only discs are pressed from a master at the time of manufacture and cannot be erased. They include the music CD, CD-ROM, DVD-ROM, DVD-Video and BD-ROM (Blu-ray). See CD, DVD and Blu-ray.

Write-Once (Burnable)
Write-once discs are recorded in the user's environment but cannot be erased. They include CD-R, DVD-R, DVD+R, BD-R (Blu-ray) and WORM discs, as well as magneto-optic (MO) and ultra density optical (UDO) discs in WORM mode. See magneto-optic disk and UDO.

Rewritable (Phase Change and Magneto Optic)
Rewritable discs can be written and re-written numerous times. Employing phase change technology, consumer-oriented products include CD-RW, DVD-RAM, DVD-RW, DVD+RW and BD-RE (Blu-ray) as well as ultra density optical (UDO). See phase change disc.

Magneto-optic (MO) disks combine optical and magnetic technologies (see magneto-optic disk). See ISO/IEC 13346, multilevel optical disc, holographic storage, WORM and legality of optical storage.

Writability  Optical Disc Types

    Read only    CD, CD-ROM
                 DVD-ROM, DVD-Video
                 BD-ROM

    Write once   CR-R
                 DVD-R, DVD+R
                 BD-R, WORM

    Rewritable   CD-RW
                 DVD-RW, DVD+RW
                 DVD-RAM
                 BD-RE

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References in periodicals archive

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An optical disk is a round disk that utilizes spiral or circular tracks similar to the vinyl recordings that were originally used for audio recording.

Introduction to Electronic Document Management Systems

The converted image then is stored on optical disks.

In pursuit of the paperless office

Such devices work like a traditional jukebox, storing many optical disks that can be called up one at a time as needed.

The paperless office

The image is then sent to the computer as a series of dots, commonly referred to as a "bitmap." This image is then compressed and stored to an optical disk.

Legal status of imaging systems and optical storage of records

The enthusiasm is less for the optical disk medium itself than for its integration with a software package that allows patient files to be retrieved in seconds, rather than hours or days as is the case with such traditional archiving tools as microfiche, magnetic tape, and paper.

Optical disk archiving: the coming revolution in data management

With an optical-disk jukebox system, the data can be downloaded from the computer to an optical disk overnight, freeing the expensive hard disk storage of the main computer for daily transactions.

Slaying the paper dragon

The voluminous patient records, reports, and tests which we once stored on paper are now kept on optical disk. Up to seven years of files are maintained for each patient and can be easily accessed when needed at the push of a button.

Imaging revitalizes department's filing system

But all three programs can be stored on a single CD-ROM disk, which employs optical disk technology.

Quenching storage thirst