There were sporadic experiments with what we would now call a graphical user interface as far back as 1962 and the pioneering SPACEWAR game on the PDP-1. The display on that machine was not just a character terminal, but a modified oscilloscope that could be made to support vector graphics. The SPACEWAR interface, though mainly using toggle switches, also featured the first crude trackballs, custom-built by the players themselves.^[8]. ITen years later, in the early 1970s these experiments spawned the video-game industry, which actually began with an attempt to produce an arcade version of SPACEWAR.

The PDP-1 console display had been descended from the radar display tubes of World War II, twenty years earlier, reflecting the fact that some key pioneers of minicomputing at MIT's Lincoln Labs were former radar technicians. Across the continent in that same year of 1962, another former radar technician was beginning to blaze a different trail at Stanford Research Institute. His name was Doug Engelbart. He had been inspired by both his personal experiences with these very early graphical displays and by Vannevar Bush's seminal essay As We May Think [Bush], which had presented in 1945 a vision of what we would today call hypertext.

In December 1968, Engelbart and his team from SRI gave a 90-minute public demonstration of the first hypertext system, NLS/Augment.^[9] The demonstration included the debut of the three-button mouse (Engelbart's invention), graphical displays with a multiple-window interface, hyperlinks, and on-screen video conferencing. This demo was a sensation with consequences that would reverberate through computer science for a quarter century, up to and including the invention of the World Wide Web in 1991.

So, as early as the 1960s it was already well understood that graphical presentation could make for a compelling user experience. Pointing devices equivalent to the mouse had already been invented, and many mainframes of the later 1960s had display capabilities comparable to those of the the PDP-1. One of your authors retains vivid memories of playing another very early video game in 1968, on the console of a Univac 1108 mainframe that would cost nearly forty-five million dollars if you could buy it today in 2004. But at $45M a throw, there were very few actual customers for interactive graphics. The custom hardware of the NLS/Augment system, while less expensive, was still prohibitive for general use. Even the PDP1, costing a hundred thousand dollars, was too expensive a machine on which to found a tradition of graphical programming.

Video games became mass-market devices earlier than computers because they ran hardwired programs on extremely cheap and simple processors. But on general-purpose computers, oscilloscope displays became an evolutionary dead end. The concept of using graphical, visual interfaces for normal interaction with a computer had to wait a few years and was actually ushered in by advanced graphics-capable versions of the serial-line character VDT in the late 1970s.