Let's get the obvious out of the way first: you cannot erase a write-once (non-erasable) disc. That does not mean you need special hardware or non-commercial software or a secret trick. It means that the changes in the dyes of a write-once blank are not reversible.
Restricting ourselves to erasable (CD-RW) media, we can look at how erasing is done. In first approximation, it works just as we write to those discs. A region corresponding to a bit is heated with a laser until it (more or less) melts, then refreezes in either mostly crystalline or mostly amorphous state depending on the heat/cool cycle used. The result is more or less reflective, hence a one or a zero.
In quick erasure, the TOC is reset to suggest that the disc is blank, but in fact the rest of the disc still has its information. This is not simply resetting one byte of the filename as on a hard drive, so recovery tools will not work to restore the information. Neither is it such complete erasure that a backup program, such as TakeTwo, will be able to use the disc. In short, Quick erase is great for routine use, but if it does not work, a Full erase is needed.
In full erasure, the whole surface is cycled and the information is really, really (honest-to-gosh) gone. A disc which was used for packets may not switch happily to mastering if you use Quick Erase - but Full Erase will probably do the trick. (I would be happy to tell you when one works and when you need the other, but I haven't figured it out yet. It seems to depend on the medium, it may depend on the recorder, but it definitely depends on more information than I've been able to collect so far. Watch this space; some day it may have the answers.)
Finally, there are two more levels of erasure - one that is likely to work and one that should not, but sometimes does. Super Blank is linked from this site. It is made to erase a batch of blanks at once on multiple SCSI drives. However, it will work on only one drive at a time if you wish and it does support most ATAPI (EIDE) drives - so try it. If the disc is sufficiently fouled up, it may report serious errors and start flashing at you. If you ignore that and let it proceed for forty minutes or so, it usually does erase the disc. Super Blank does only Full erase and theoretically does it no better than any other full-erase program. In practice, it seems to work where others do not.
Another solution that should not work - but may - is solar assist. When you put a disc into a drive, job number one is to determine what the disc is. To do that, the TOC is read and the runout track is checked. If the drive is a reader, it does not need a runout track, but in any drive, there must either be a TOC or no TOC at all. If there's a part of a TOC or a faulty one, the drive will keep looking... Forever. If a disc won't stop spinning in a reader, try it in your writer; if there's no runout track (blank, open session, etc.), it will settle down there. But if the TOC is fouled, it will not stabilize even in the writer and violent means are called for.
On occasion, a 'dead' erasable - one which would not stabilize - can be made to look blank enough to be erased by exposing it to strong sunlight for a few hours. Whether it's heat, ultraviolet or black magic, it sometimes works. No sun? Try an EPROM programmer or other intense UV source. No guarantee, nothing but hope that something might save that scrap of metallized plastic.
A final note on Adaptec; the story may be similar with products of other publishers. There are two ways to erase in Easy CD Creator 4. A separate CD Eraser is included with Direct CD; it only offers Quick erase. For the option of Full or Quick, you need to use the Erase function on the CD menu of the ECDC core program. Since Full erasure is needed primarily for DCD functions (including the DCD-related TakeTwo), this is characteristic forgetfulness. You have Full capability where you don't need it, but not where you do.
E-mail me at cdrecording@mrichter.com
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