Shell Windows, DOS Boxes and Real Teletypes

If you are old enough, you might remember that 'shell' windows and 'DOS boxes' on graphical user interfaces are a virtualization of physical terminals that were connected over a serial interface to a mainframe computer. Sounds pretty ancient today, doesn't it!? But actually that wasn't the beginning as those hardware terminals with keyboards and screens were themselves a virtualization of the initial input output device connected to a computer over a serial interface: A mechanical teletype machine and paper tape reader.

When I recently did some history research I came across this video on YouTube that shows how an original teletype machine was used before the days of hardware terminals with screens to load programs from paper tape into an Altair 8800, the first personal computer. Once the program is loaded the teletype is then used to type-in instructions and programs and see the result printed out on paper. One thing is for sure. After watching this video you'll never quite look at a shell window and a blinking cursor as before.