An optical disc drive is a memory storage and retrieval device which can read (and sometimes write) data to an |optical disc|. The drive may be internal, fitting in a drive bay, or external, housed in its own case. The external drive is connected to the system by a |data cable|. The optical disc drive uses a high intensity light source, such as a laser, to read digital data.
Several types of optical disc drives are presently in use, differing primarily in their manipulation of the data. These types include: the Read/Write Optical Drive, CD-ROM Drive, and WORM Drive. A similar type of disc drive technology uses the ~floptical~ disc.
The Read/Write Optical Drives can both read and write data on an optical disc. The ~magneto-optical~ nature of the disc is such that a laser is capable of registering the orientation of magnetic data as well as reversibly altering their orientations. These drives are preferred over other types of optical drives, even though they are generally more expensive than the CD-ROM or WORM drives.
The CD-ROM drive is distinctive for its ability to read, but not write data to the optical disc. CD-ROM technology is desirable for storage of large databases, such as encyclopedias or libraries, which do not require alteration of the data.
The ~WORM~ drive can read data on the optical disc, but can only write the data once, irreversibly. This technology, though not widely used, is implemented by banks to construct a database which may not be altered or erased.
The "floptical" drive does not actually use an optical disc, but combines elements of magnetic and optical drives. This diskette is magnetic, but the drive uses a laser to synchronize the tracking of the diskette. This greatly increases the data density.
