What is a WORM disk ?

WORM stands for write-once read many. It is a type of Optical disk. WORM disks allow the users to create their own CD-ROM disks by using a CD-recordable (CD-R) drive, which can be attached to a computer as a regular peripheral device. WORM devices were developed in the late 1970s and have been adapted to a number of different media. The discs have varied in size from 5.25 to 14 inches wide, in varying formats ranging from 140MB to more than 3GB per side of the double-sided medium. WORM disk, which look like standard CD-ROM  disks, are purchased from blank and encoded using a CD-R drive. The information recorded by a WORM disk by a CD-R drive can be a read by any ordinary CD-ROM drive. As the name implies, data can be written only once on a WORM disk, but can be read many times.

Data is written to a WORM disc with a low-powered laser that makes permanent marks on the surface. That is, as  with a CD-ROM disk, once data has been etched on to the surface of a WORM  disk , it becomes permanent , which can be a read, but never altered. Moreover , writing on a WORM disk cannot be done in multiple sessions and all the data to be recorded have to be written on the disk surface in a single recording session.