Time-sharing
In computing, time-sharing is the sharing of a computing resource among many users by means of multiprogramming and multi-tasking at the same time.
Its introduction in the 1960s by students and professors at Dartmouth College, and emergence as the prominent model of computing in the 1970s, represented a major technological shift in the history of computing.
By allowing a large number of users to interact concurrently with a single computer, time-sharing dramatically lowered the cost of providing computing capability, made it possible for individuals and organizations to use a computer without owning one, and promoted the interactive use of computers and the development of new interactive applications.
History
Batch processing
The earliest computers were extremely expensive devices, and very slow in comparison to later models. Machines were typically dedicated to a particular set of tasks and operated by control panels, the operator manually entering small programs via switches in order to load and run a series of programs. These programs might take hours, or even weeks, to run. As computers grew in speed, run times dropped, and soon the time taken to start up the next program became a concern. Batch processing methodologies evolved to decrease these "dead periods" by queuing up programs so that as soon as one program completed, the next would start.