Time-sharing is the idea that a single computer can serve many users at once, giving each the feeling of having the machine to themselves. The computer switches its attention rapidly among users, so while one person thinks at a terminal, others get their work done. This replaced batch processing, in which programmers handed in stacks of punched cards and waited, sometimes for hours, to get results back.
The contrast was stark. As the Multicians history of the IBM 7094 describes, MIT’s machine first ran under a batch system where jobs “were submitted on cards, transferred to tape, and processed sequentially.” MIT’s Compatible Time-Sharing System, CTSS, demonstrated in the early 1960s that interactive shared access was practical and far more pleasant to use.
The promise of time-sharing motivated the Multics project. Its 1965 introduction paper praised “the availability at one’s fingertips of facilities for editing, compiling, debugging, and running in one continuous interactive session,” and framed the goal as a computer utility serving a community of users.
Time-sharing reshaped how people relate to computers. It made interactive, conversational computing normal, encouraged shared file systems and electronic mail, and set the expectations that desktop and cloud computing still meet today. Unix grew directly out of this tradition.