Is the session Closed?
(Especially with the method discribes in the other reply of writing to it as a floppy disc)
This applies only to CD-R disks.
With Adaptec, you can toast a cd-rom and leave the session open so you can add more data in a second toast.
After reaching the capacety limit, adding is afcouse out of the question.
"Deleting" however is still possible.
But, the deleted dataspace cannot be used again.
See to the inner part of the datalayer.
Compare it to a good and readable toasted CD-R.
If you notice any difference in the thickness of the "Unwrited" ring in the datalayer at the middle, there is an unclosed session where the "unwrited" datalayer has its thickest ring.
from the spindle-hole out, there is first a part who has no recording surface.
that is followed by a "Ring" who is actually the indicator that this is the read/write side of a disc.
This ring is clearly visible and feelable.
From the outside of that ring, the beginning of the written data should not further away then .50 Cm (app. .20 In)
Is ther more than this, the session is Unclosed, and not every program can read those disks.