... primary storage at once, but still only one program could run at any one time. The operating system could run any program it chose, thereby preventing waste of time during operator actions. There were many bugs in the large operating systems. This led to the rapid urge of the discipline of "Software Engineering". The Ethernet Local Area Network Standard was defined in the 1970's. Encryption became common over communication lines, for security purposes. The development of Personal Computers and Workstations was a revolution in 1980's, which caused a trend away from multiprogramming and interactive timesharing on large main frames, towards single user operating systems again. The use of applications packages became common in business environments, e.g. Spreadsheet, Word Processor. The windows system user interface was presented as another revolution, but was in fact based on systems developed in the early 1970's. The most important developments for the 1990's would be Distributed Computing. The ...

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