“Calculate source directory checksums” is a verification strategy used to ensure that a directory’s content has not changed. This strategy is employed by the ASCMHL standard, and involves computing checksums based on all child files and directory checksums. This detects if a folder’s contents match another folder exactly or not.

The second option, “Source Integrity Verification”, performs an additional read and checksum calculation on the source after the copy job is complete. This ensures that there were no changes to the source while copying and provides additional protection against overheating drives. It comes at the cost of re-reading the source, meaning it takes extra time to calculate the checksums again.