Seal the media source first

The Before Copying group of the plan sheet holds two switches: Seal the media source first and Copy anyway if the seal finds a problem.

A seal hashes the media source where it stands and records each file as original. The offload then compares each copy against that record. The job records a copy that agrees as verified. If the media source no longer matches its seal, the job records that file as failed.

Seal the media source first

Switch	What the job does
On	Read the whole media source and record its hashes. Then copy.
Off, and the media source holds a history	Check the copies against the generations it already holds.
Off, and the media source holds no history	Copy with nothing to check against. The job records every file as original.

The switch costs a full read of the media source. The subtitle of the row says how many bytes that is, and which generation the seal will write.

Turn it on for a media source that comes straight out of a camera and holds no history. Leave it off for one that was sealed already, because a second seal records nothing that is new. The plan warns you with folder is already sealed in that case.

A change to either switch computes the plan again, under the same job. You can never approve a plan that belongs to the setting you left.

Copy anyway if the seal finds a problem

The sheet shows this second switch only while the first one is on. It says what the job does when the seal pass itself records a failure, for example a file the media source can no longer read.

Switch	What the job does
Off	Stop before copying. The job writes nothing to any destination.
On	Copy anyway. The failure stays in the record.

Off is the safe answer, and it is the one the sheet starts with. The job then fails with the seal failed for N of M files; nothing was copied.

Turn it on when the media source is damaged and a partial copy is better than none. The manifest records which files failed, so the record still says what happened.