How does robocopy walk through a directory tree

Hi all,

could someone explain to me how robocopy "walks" through a directory tree?

It is not alphabetically, or from big to small. Looking at the ressource monitor ist seems that robocopy processes the directories randomly.

How could i calculate how long it will need to finish?

I start Robocopy with these parameters on a Server 2008 R2:

Source Dest /MT:16 /MIR /NP /COPYALL /W:1 /R:1 /LOG:Logfile

At startup the logfile contains only the header (in older versions of robocopy the logfile was written directly).

only after robocopy finished the logfile is written and the files listed are in alphabetically order.