Alan Kay presenting Ivan Sutherland’s Sketchpad, one of most influencial programs in the history of graphical user interfaces. Sutherland developed Sketchpad in 1963. This video was extracted taken from a longer one (here)…
Close to the end the lecturer is complaining about “blood running out of one’s hand” while using the light pen and how a bad input device it was. I guess they hadn’t heard of ‘carpal tunnel syndrome’ back then. That one really hurts.
Sketchpad was amazingly prescient. Periodically throughout computer and UI history you’ll see these pivotal hourglass choke points to which nearly all subsequent work can trace its roots; Sketchpad was one such point. Another is Doug Engelbart’s “Mother of all Demos” in 1968, which you can dig up on YouTube.
Ivan Sutherland, by the way, later co-founded Evans & Sutherland, who used to make insanely high-end flight simulators for the military. Today they make digital planetarium systems!