DVD FAQ?
Well one, at least: • alt.video.dvd FAQ WORM drives A large number of technologies have been introduced to provide storage of large amounts of information on optical platters with varying degrees of flexibility. The earliest were called WORM (Write Once Read Many) drives. Writing resulted in an irreversible change in an information layer. Thus, data could be written but not erased and rewritten (though just erasing a block might be possible). Heating with the writing laser beam resulted in damage (ablating) of a coating. Reading is similar to that used for CDs and other optical technologies. Typical capacity was 650 MB per side. Disks could be one sided or two sided. This is somewhat similar to the technology used in CD-R drives though many variations have been developed which vary mostly in the details. Unlike CDs, MDs, and LDs, these optical discs are formatted more like hard drives or diskettes with circular (not spiral) tracks and fixed sectors – some of which are visible to the na
