Shared Variables: Difference between revisions

Revision as of 04:26, 10 June 2007

Revision as of 02:55, 4 November 2007

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'''Shared Variables''' are a feature of the [[APL programming language|APL]] language which allowed mainframe APL programs to communicate with other facilities on a computer, which could include external files, DBMS, or other users. Shared Variables were first introduced by [[International Business Machines Corporation|IBM]] in their APL.SV program product in 1973 and continue to be available today in IBM and Dyalog APL for [[Linux]] and Windows.

The Shared Variable facility is roughly analagousanalogous to a Windows out-of-process server today.

When APL\360 was first introduced in 1968, there were no built-in means by which a user could directly access data from outside of the APL system. Some of the timesharing vendors began offering an external file system at the time, however IBM's approach was to supply a more generic facility whereby an external process could be used by an APL program. Following APL.SV, the IBM VS APL and APL2 program products also supported shared variables, as well as the [[IBM 5100]] line of computers.