Sometimes (and in particular the last two times I restarted), a strange bar looking like a load bar or a copy bar appears on the restart screen, as in the image below.
I am running Mac OS X 10.9.5. What is it? Is it just the installation progress of updates (that install without me saying anything but that is another story) or is it something else?
Note
It has oftimes happened to me that I saw this:
Is it correct to call that "freezing"? If not, what is the correct name? And is it any different from hibernation aka deep sleep?

