Having animated stripes on a progress bar might be useful to indicate that the system is still running and the computer did not hang up.
Should the stripes be on the entire progress bar (with semi-transparent filled part) or just the filled part? and why?
the following snippet shows the entire bar animated
http://jsfiddle.net/alsadi/DjzL4/
NOTE: Bootstrap chose to the second option http://getbootstrap.com/components/#progress-animated