
Pilot / ViewPoint

Launched: 1977
Pilot is a single-user, multitasking operating system designed by Xerox PARC in early 1977, written in the Mesa programming language, with a total of approximately 24,000 lines of code, for the Xerox Star computer.
It was later rewritten to improve performance on the new Xerox 6085 hardware and renamed ViewPoint for its release in 1985.