Unix was born in 1969 out of the mind of a computer scientist at Bell
Laboratories, Ken Thompson. Thompson had been a researcher on the Multics
project, an experience which spoiled him for the primitive batch computing
that was the rule almost everywhere else. But the concept of timesharing
was still a novel one in the late 1960s; the first speculations on it had
been uttered barely ten years earlier by computer scientist John McCarthy
(also the inventor of the Lisp language), the first actual deployment had
been in 1962, seven years earlier, and timesharing operating systems were
still experimental and temperamental beasts.

Computer hardware was at that time more primitive than even people who
were there to see it can now easily recall. The most powerful machines
of the day had less computing power and internal memory than a typical
cellphone of today. Video display terminals were in their infancy
and would not be widely deployed for another six years. The standard
interactive device on the earliest timesharing systems was the ASR-33
teletype - a slow, noisy device that printed upper-case-only on big
rolls of yellow paper. The ASR-33 was the natural parent of the Unix
tradition of terse commands and sparse responses.

When Bell Labs withdrew from the Multics research consortium, Ken
Thompson was left with some Multics-inspired ideas about how to build a
file system. He was also left without a machine on which to play a game
he had written called Space Travel, a science-fiction simulation that
involved navigating a rocket through the solar system. Unix began its
life on a scavenged PDP-7 minicomputer, as a platform for the Space Travel
game and a testbed for Thompson's ideas about operating system design.

[adapted from https://www.catb.org/esr/writings/taoup/html/ch02s01.html]