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The Mother of All Demos

SRI · San Francisco · 9 December 1968

The Demo

Ninety minutes in which a thousand computer professionals saw the mouse, hypertext, windows and shared editing arrive as one working system.

An NLS workstation in 1968: a researcher between two large cathode-ray tube displays, one hand on the mouse, the other on a five-key chord keyset.

An NLS workstation at SRI in 1968 — mouse at the right hand, keyset at the left. Photograph: SRI International, CC BY-SA 3.0.

01

The room

One man, one console, no second take

The Fall Joint Computer Conference filled the Civic Auditorium. Engelbart sat alone on stage in a headset, his display projected twenty-two feet above him. The computer answering him was in Menlo Park, thirty miles away.

Two microwave links carried the picture down the peninsula and back; a leased line carried the keystrokes; a borrowed projector put it on the wall. Seventeen people ran cameras, mixers and cues at both ends. It was live, continuous and unrehearsed.

Douglas Engelbart in 1968, seated at a desk wearing a headset, mid-sentence, a chalkboard of plotting commands behind him.

Douglas Engelbart at SRI, 1968. Photograph: SRI International, CC BY-SA 3.0.

02

The vocabulary

Six ideas, demonstrated together

The achievement was not any one of them, but that they arrived as one system, each making the others worth having.

  • Pointing — a cursor tracking a hand across a desk.
  • Linking — any word carrying an address to another document.
  • Windows — the screen divided into independent, resizable views.
  • Structure — every line belonging to a hierarchy you could operate.
  • Shared editing — two people in one file, each with a visible pointer.
  • Presence — a face and a voice sharing the screen with the document.
A woman at a 1969 display console reaching a light pen to a screen of glowing text, a bank of round function buttons at her left.

The same console, with its bank of function buttons. Brown University, 1969. Photograph: Gregory Lloyd, CC BY 2.0.

03

The screen

What a screen was in 1968

A computer display was a laboratory instrument: glowing vector strokes on a phosphor tube, priced in thousands. Most people who used a computer never saw one — they handed in a deck of cards and collected paper hours later.

Engelbart's argument was that a screen is not an output device. It is where thinking happens, and the pointing, the linking and the structure all follow from taking that seriously.

Over-the-shoulder view of a 1969 hypertext console: light pen touching a line of text on a curved cathode-ray tube.

Not the 1968 demonstration: the Hypertext Editing System at Brown University, October 1969, a light pen selecting one line of linked text. Photograph: Gregory Lloyd, CC BY-SA 4.0.

The recording still exists

All ninety minutes were filmed, and the film survives — slower than a modern launch, and stranger than most science fiction.

Watch the full ninety minutes

The future

was shared.