Re: CRC verify on ntbackup
"Chandra" <email@example.com> wrote in message
> I have been trying to find out what the crc verify actually does on
> ntbackup. I don't understand crc very well, can anyone give me a brief
> explanation. Does it include a crc tag for each file and then compare
> crc's from the original file when finished? If so does it mean that
> it is file by file verification and if there are multiple errors
> within the file it may escape notification because CRC only catches
> certain types of errors.
> I am planning on using ntbackup on win2003 for backups and would like
> to know how reliable it is for backup and recovery.
CRC (Cyclic Redundancy Check) is a method commonly used
at a hardware level to confirm the validity of data read off some
storage medium. Each packet read from the storage medium has
a CRC byte attached. The packet is processed by the CRC
checker, and if its output does not agree with the CRC byte
then the data is declared invalid.
CRC errors are bad news. They tell you that the data could
not be read successfully off your medium. It's like me putting
the word "security" into this text, and you seeing "sekurity"
instead. There is no such word in the English language,
hence you must assume that something went wrong in the
transmission of this messsage.
CRC has nothing to do with file verification, and everything
with validating data as it is read off your tape.