Sketchpad with Sutherland at the controls Finished drawings could be stored on magnetic tape and re-edited at a later date. Previously drawn primitive objects could be recalled and rotated, scaled and moved. A light pen provided co-ordinates for drawing commands entered using the keyboard. It used a scale of 2000:1, making the virtual drawing space huge, and pioneered techniques such as “rubberbanding”, zooming and object-oriented drawing. Sutherland introduced many of the graphical conventions we now take for granted. Sketchpad may look obvious and under-powered as a drawing program from today’s perspective but nothing like it had existed before. and so this is yet again another tale of late night programming! As a graduate student the only time he could get the TX-2 to himself was between 3.00 and 5.00 a.m. Sutherland's PhD thesis was entitled “ Sketchpad: A Man-Machine Graphical Communication System”. Ken Thompson salvaged a PDP-1 and started writing Unix just with the aim of playing SpaceWar!)
(SpaceWar is also responsible for the creation of the Unix operating system. Sutherland was impressed and he decided that the TX-2 should be a good machine with which to implement a realtime drawing program. The sun had gravity and there were lots of extra complications to be mastered before you could blow your enemy’s ship up. Two space ships on opposite sides of a sun fired missiles at each other. This was probably the first graphics-based game. Graduate students began to play Spacewar on the TX-2. The atmosphere of academic freedom at MIT allowed some students to start to think of more exciting lines of research.
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