In
computer science, the concept of protected procedure, first introduced as protected service routine in 1965, is necessary when two computations ''A'' and ''B'' use the same
routine ''S''; a protected procedure is such if makes not possible for a malfunction of one of the two computation to cause incorrect execution to the other.
[Dennis 66]
One of the most important aspects of Dennis and Van Horn (hypothetical) system "supervisor"
was the inclusion of a description of protected procedure.
[Levy 84, pp.46-6]
In a
global environment
In computer programming, a global variable is a variable with global scope, meaning that it is visible (hence accessible) throughout the program, unless shadowed. The set of all global variables is known as the ''global environment'' or ''global s ...
system (where there's some shared variable), the protected procedure mechanism allows the enforcement of the
principle of least privilege and the avoidance of
side effects in resources management (see
Denning principles
Peter James Denning (born January 6, 1942) is an American computer scientist and writer. He is best known for pioneering work in virtual memory, especially for inventing the working-set model for program behavior, which addressed thrashing in o ...
).
Footnotes
References
*
Dennis, J. B., and Glasee, E. ''The structure of on-line information processing systems''. Information Systems Sciences: Proc. Second Cong., Spartan Books, Baltimore, 1965, pp. 1–11
*J. B. Dennis and
E. C. Van Horn.
Programming Semantics for Multiprogrammed Computations'. Communications of the ACM 9(3), March 1966.
*
Concurrent computing
Subroutines
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