rodney@solar.card.inpu.oz.au (Rodney Campbell) (05/29/91)
cmoore@alioth.mit.edu (Christopher B. Moore) writes: >I have noticed that a number of rewritable optical disk drives are also >advertised as capable of reading and writing WORM disks. What is a >WORM disk? I know, "write once, read many," but does writing to the disk >involve actually burning the bits into a medium of some sort or is it, in >the end, a magnetic process just like a rewritable disk? If the >WORM disks have had the bits burned into them, is it possible to read them >with CD-ROM drives? The Erasable Optical and Worm disks are very unlike CD-ROM disks. The disks have a solid case which surrounds the disk and the disk platters themselves are generally much thicker than CD-ROMs (which are exactly the smae as music CD's). The organisation of the disk for an Erasable Optical and Worm is also different to the CD-ROM so I do not believe you could get the CD-ROM drive to read the others even if you could get the sucker into the drive. With the WORM you cannot change the data once it has been written to the disk and in fact if you use it for a standard file system and change any files the old area of the disk where the file was is ignored and a new section is used for the changed file. >On the subject of rewritable optical disks in general, it is possible to read >disks written on one manufacturer's drive with a drive manufactured by someone >else? Does anyone have any experience with rewritable optical disks in >general? As long as the manufacturers conform to standards - Yes. Many manufacturers support the ISO format standard (eg Sony and the ISO Maxtor - approx 650 MB per disk) but some have come up with their own format (for example the Maxtor 1GB format using ZCAV [Zoned Constant Angular Velocity]). There are also two standard ISO formats type one and three which may not be compatible. There are some drives which only support type one (the older) [I know of one multifunction drive]. Also some vendors I believe put a signature checking thingy in their drive or software which will only accept disks from a certain vendor. Hope that this helps... Rodney... _______________________________________________________________________________ Rodney Campbell - Telecom Aust |MHSnet: rodney@card.inpu.oz.au Network Services |Snail : 8th Floor, 91 York Street, Sydney 2000. Customer Applications Research | or PO Box A226, Sydney South 2000, Australia. & Development |Phone : +61 (0)2 364 3346 Fax: +61 2 262 3813