Time-sharing

[4] Comparatively inexpensive card punch or paper tape writers were used by programmers to write their programs "offline".

This situation limited interactive development to those organizations that could afford to waste computing cycles: large universities for the most part.

[6][8][9] In a paper published in December 1958, W. F. Bauer wrote that "The computers would handle a number of problems concurrently.

"[10] Christopher Strachey, who became Oxford University's first professor of computation, filed a patent application in the United Kingdom for "time-sharing" in February 1959.

[11][12] He gave a paper "Time Sharing in Large Fast Computers"[13] at the first UNESCO Information Processing Conference in Paris in June that year, where he passed the concept on to J. C. R.

These include SAGE (1958), SABRE (1960)[6] and PLATO II (1961), created by Donald Bitzer at a public demonstration at Robert Allerton Park near the University of Illinois in early 1961.

DTSS's creators wrote in 1968 that "any response time which averages more than 10 seconds destroys the illusion of having one's own computer".

[26] With the rise of microcomputing in the early 1980s, time-sharing became less significant, because individual microprocessors were sufficiently inexpensive that a single person could have all the CPU time dedicated solely to their needs, even when idle.

Expensive corporate server farms costing millions can host thousands of customers all sharing the same common resources.

As with the early serial terminals, web sites operate primarily in bursts of activity followed by periods of idle time.

This bursting nature permits the service to be used by many customers at once, usually with no perceptible communication delays, unless the servers start to get very busy.

Companies providing this service included GE's GEISCO, the IBM subsidiary The Service Bureau Corporation, Tymshare (founded in 1966), National CSS (founded in 1967 and bought by Dun & Bradstreet in 1979), Dial Data (bought by Tymshare in 1968), AL/COM, Bolt, Beranek, and Newman (BBN) and Time Sharing Ltd. in the UK.

[30][31] In 1975, acting president of Prime Computer Ben F. Robelen told stockholders that "The biggest end-user market currently is time-sharing".

[citation needed] Although many time-sharing services simply closed, Rapidata[35][36] held on, and became part of National Data Corporation.

[38] Even as revenue fell by 66%[39] and National Data subsequently developed its own problems, attempts were made to keep this timesharing business going.

To prevent this from happening, an operating system needed to enforce a set of policies that determined which privileges each process had.

The first international conference on computer security in London in 1971 was primarily driven by the time-sharing industry and its customers.