Back in the 1980s, when I was programming for Geac Computers (long before Windows, object oriented or anything of the sort) we didn't have progress bars, but we did try to show that something was happening.  For this we continually sent a stream of characters to the screen, which were  | / - \ with each character followed by ctrlH (backspace)  It looked a little like a small rod rotating rather like a baton.