Whether the newest stored image predates the chunk codec, so re-imaging would shrink it.
The producer skips a site whose recorded generation is current, so an unpacked image (3.57x its
packed size) would never re-image on its own; the alarm reads this to clear that generation once.
A zero raw_bytes on any chunk is enough (the codec writes it on every packed row, and only an
incompressible chunk is legitimately zero); a false positive costs one re-image.
Whether the newest stored image predates the chunk codec, so re-imaging would shrink it.
The producer skips a site whose recorded generation is current, so an unpacked image (3.57x its packed size) would never re-image on its own; the alarm reads this to clear that generation once.
A zero
raw_byteson any chunk is enough (the codec writes it on every packed row, and only an incompressible chunk is legitimately zero); a false positive costs one re-image.