An unrecoverable data error is defined as a failure of the drive to recover data from the media. These errors occur due to head/media or write problems.
Unrecoverable data errors are only detected during read operations, but not caused by the read. If an unrecoverable data error is detected, a MEDIUM ERROR (03h) in the Sense Key will be reported. Multiple unrecoverable data errors resulting from the same cause are treated as 1 error.
