Rather than simply deletingfiles - which could then be undeleted - the worm resets the file size to zero bytes, making them much more difficult to recover.
The 4420 will also offer "random erase technology" that lets you use a CD-RW disc just like a floppy or hard disk -- adding or deleting individual files at any time.
We judge CD-RW packet-writing performance by copying a folder containing 100MB of files to a CD-RW disc three times: first to the newly formatted blank disc, again after deleting the files from the first copy operation, and finally by overwriting the files from the second operation.