CDs and DVDs don't last forever. Even under the best possible environmental conditions, some writeable media don't...
last for more than a few years. The photo-sensitive dye used in writeable CDs and DVDs can degrade over time, rendering unreadable what might be the only backup copy you have of a particular file. If something goes wrong on such a disk, you'll want to know about it -- or, better yet, be able to recover the data if possible.
The freeware utility CDCheck, created by Mitja Perko, performs error-checking on removable media of all kinds, but specifically recordable media such as CD-R and DVD+/-R/W. If you've just burned a CD or DVD, you can run CDCheck and create a hash file that verifies the integrity of all the files on the disk. Later, you can run CDCheck to ensure that the files on the disk still match against the hash file you created initially.
Checking a single-layer DVD (about 4.45 GB of data) on a 32x DVD-ROM drive takes about 15 minutes. If there's no hash file for a disk, you can still run a check against the disk's native CRC information. The program can also compare the contents of two directories, as, for instance, a way of hash-checking an original against a copy.
Now in version 3.1.9, the program can compare audio CDs, too, which it sees as data CDs with .WAV files. CDCheck also has full support for Unicode directory and file names, large volume sizes (i.e., greater than 4 GB for dual-layer DVDs) and detailed reporting about media metadata based on the manufacturer-supplied information. Note: The media metadata is not always totally accurate, but it can be useful for inventory purposes.
Serdar Yegulalp is editor of the Windows Power Users Newsletter. Check it out for the latest advice and musings on the world of Windows network administrators -- and please share your thoughts as well!