The Xerox Alto, which debuted in the early spring of 1973 at the photocopying giant’s newly established R&D laboratory, the Palo Alto Research Center (PARC). It seems so uncannily familiar today for one reason: We are now living in a world of computing that the Alto created.

The Alto was a wild departure from the computers that preceded it. It was built to tuck under a desk, with its monitor, keyboard, and mouse on top. It was totally interactive, responding directly to its single user.

In contrast, the dominant mainframe at the time—IBM’s hugely popular System 360, heavily used by big organizations, and the Digital Equipment Corp.’s PDP-10, the darling of computing researchers—were nothing like the Alto. These and the other mainframes and minicomputers of the era were room-size affairs, almost always located somewhere away from the user and almost always under the control of someone else. The many simultaneous users of one such computer shared the system as a common resource.

Steve Jobs and a whole team from Apple toured PARC in 1979. The visit was arranged as a quid pro quo for allowing Xerox to invest in Jobs’s exciting new personal-computer company. Viewing Alto’s graphical user interface, Jobs had what he later described as an epiphany, one that reoriented his efforts at Apple forever after.

See a restoration video below and read more about Alto and the revolution it sparked in IEEE Spectrum.