A number of companies manufacture WORM drives but follow no single standard. therefore,a WORM disk written on one manufacturer's drive is quite unlikely to be readable on another manufacturer's drive. Each manufacturer(sometimes small groups of manufacturers) uses its own proprietary data format and disk capacity and many use a cartridge size only their drives can handle. For example, most WORM drives are designed for 5 �-inch cartridges, but some WORM drives handle only 12-inch disks. In addition, although most WORM drives interface the computer via SCSI host adapter, others use different interfaces, some of them proprietary.
Certainly, at least in part because of these incompatibility problems, WORM drives are not big sellers. No more than several thousand are sold each year at prices soaring to the heights-some 5 �-inch drives cost several thousand dollars. The 5 �-inch-drive cartridges, with range in capacity from 650M to 1.3G, can cost more than $180.
The term niche market is used occasionally to describe a computer product or peripheral that lacks broad appeal or usefulness. Because of its cost and incompatibility problems, WORM drive technology is a niche market product. Unless you must be able to store massive amounts of data and ensure it can never be altered, you are better off buying a magneto-optical drive, or perhaps even a tape backup drive.
