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This paper discusses both the history and future of programming languages (= higher level languages). Some of the difficulties in writing such a history are indicated. A key part of the paper is a tree showing the chronological development of languages and their interrelationships, Reasons for the proliferation of languages are given. The major languages are listed with the reasons for their importance. A section on chronology indicates the happenings of the significant previous time periods and the major topics of 1972. [ABSTRACT FROM AUTHOR]

This paper discusses modularization as a mechanism for improving the flexibility and comprehensibility of a system while allowing the shortening of its development time. The effectiveness of a "modularization" is dependent upon the criteria used in dividing the system into modules. A system design problem is presented and both a conventional and unconventional decomposition are described. It is shown that the unconventional decompositions have distinct advantages for the goals outlined. The criteria used in arriving at the decompositions are discussed. The unconventional decomposition, if implemented with the conventional assumption that a module consists of one or more subroutines, will be less efficient in most cases. An alternative approach to implementation which does not have this effect is sketched. [ABSTRACT FROM AUTHOR]

This paper presents an approach to writing specifications for parts of software systems. The main goal is to provide specifications sufficiently precise and complete that other pieces of software can be written to interact with the piece specified without additional information. The secondary goal is to include in the specification no more information than necessary to meet the first goal. The technique is illustrated by means of a variety of examples from a tutorial system. [ABSTRACT FROM AUTHOR]

Finite-length reference string of arbitrary structure are considered, and an exact expression for average working set size in terms of "corrected" interreference interval statistics is derived. An example is discussed; upper and lower bounds are obtained; and the average working set size function is shown to be efficiently obtained for a set of page sizes, in a single pass of the reference string. This work follows the developments of a paper by Denning and Schwartz, who consider infinite-length reference strings which satisfy certain statistical properties and who derive an expression relating the asymptotic average working set size to the asymptotic missing page rate function under working set replacement. [ABSTRACT FROM AUTHOR]