nishri@gpu.utcs.toronto.edu (Alex Nishri) (02/10/88)
In article <806@PT.CS.CMU.EDU> ralphw@IUS3.IUS.CS.CMU.EDU (Ralph Hyre) writes: >I'm looking for information (rumors,even) about CD-WORM drives. >This would presumably be a CD-ROM transport with a higher-power laser for >burning pits into the disc for data storage. Similar technology >already exists for 8" and 12" optical media, why not for compact disc? This isn't quite what you asked for, but is related. If you are interested in one possible future method for giving you read/write discs with the density of today's CD-ROM discs, take a look at the February 1988 IEEE Spectrum. There is an article in there about a readable/writeable disc using magnetic and optical technology. The following is a grossly simplified summary. Basically it consists of an infared laser beam which can heat up the special material of the disc. This special material, at high temperatures is easily altered by a weak magnetic field. At room temperature even a fairly strong magnetic field has no effect. This means that only the spot heated by the infared beam is effected by the weak magnetic field. To read such a disc, a laser is aimed at the spot to be read. The polarized light is changed depending on the data value recorded at that spot. This optical/magnetic technology has been known for years, but the problem has always been that the special material has broken down quickly due to the high heat it was subjected to. It was literally cooked ... :-} Recently, changes have been made to the special material allowing more writes per disc without "cooking". The IEEE Spectrum article predicted products would become available by late this year. Alex Nishri University of Toronto Computing Services