A 5 1/4″ Optical Digital Data Storage Drive

A number of Optical Digital data storage devices were introduced in recent years. Most of these devices use a 12" diameter write-once-read-mostly (WORM) optical disk with a capacity around 1 GByte per disk side. These devices are aimed at the high end of data storage hierarchy, and larger capacity is also necessary to bring the cost per bit to a reasonable value when the cost of laser and optics are high at the early stage of development. Much progress has been made in the past two years. The success of laser diode based compact audio disk players in the market place has changed this situation dramatically. It is now economically feasible to produce optical digital recording devices with a formfactor of a 5 1/4" Winchester drive, using a 130 mm diameter WORM disk, to store 200 MByte/side, and compete favorably with existing magnetic recording devices on a cost per bit basis.