ZIDRAV stands for "Zorba's Incredible Data Repairer And Verifier", and is an
extremely useful tool for cross-checking files that have been transfered via
HTTP, FTP, or some other method. What it does, is generates a checksum file,
and then by comparing that checksum with the original file, it creates a patch
file that can repair the corrupted file. Very cool, and saves re-downloading.