[Syzygies]

This hard linking feature is a command line one-liner, "cp -al", if one can make a parallel directory on the same file system. As far as I can see, SD! will only copy to volumes as targets, not subdirectories like Retrospect's "subvolume" feature. Also, SD! deletes everything else that it finds on the target. If SD! could loosen either of these behaviors, then the above one-liner would trivially support archiving as described in this thread.

There are other, tamer reasons to want SD! to copy directory to directory, as an option. If this is one's goal, with the current filtering setup SD! wades through all the other files on the volume, rather than restricting its focus to a given directory. For my directory -> disk image tasks, on updates this is where half the time goes.

There are other, tamer reasons to want SD! to have filtering to protect certain target files from deletion. This is dumb, but for example I like my backup volumes to have a different label color. Etc. Etc.

I played around for a bit looking for a hack to present a local directory as a volume. E.g. adding mounts using Netinfo Manager, trying to connect to afp://localhost. Nothing worked. There should be a routine way to mount a folder so it appears to be a mounted volume, but googling didn't turn up one for me.