[DGD] Primary vs secondary snapshot

[Raymond Jennings]

First question:

I noticed that during creation of an incremental snapshot, the full
snapshot is moved to blah.old, and the swapfile is moved to blah and
further swapping goes to blah as the incremental snapshot, while the full
snapshot remains at blah.old

Is this correct?

Second question:

If so, is there any way to distinguish a full blah and a stale blah.old
from a full blah.old and an incremental blah without having the mudlib
posting a file somewhere for external scripts to read?