A numerical profile of commercial PL/I programs

Abstract

A sample of 120 production PL/I programs from several commercial computing installations has been studied. Data about the programs in the sample have been extracted by a PL/I scanning program. The statistical results of the study are presented in this document The paper concentrates on statistical data and not on general conclusions. The data are only interpreted to the extent that it is not ill‐defined and misleading. The data profile the use of basic PL/I elements and the structure of programs written in PL/I. The reader of this report will get a better understanding of how PL/I has been used in the commercial environment up to 1974.

A Domain Strategy for Computer Program Testing.

“…Elshoff (5,6] studied 120 production PL/I programs and showed similar results, including the fact that 97% of all aritheetic operators are + or -, and 98% of all expressions contain fewer than two operators. …”

Methodologies for Computer Program Testing.

“…Next let us consider two further assumptions : ( 5 ) predicates are simp l e ; and ( 6 ) adjacent domains compute different functions.…”

“…If assumptions ( 5 ) and (6) are imposed , the testing strategy is considerably simpl ified , as no more than one doma in need be examined at one time in order to select test t~oints. Moreover , the number of test point s required to test each dn~~in grows linearly with both the dinens ionalitv of the input space and the number of predicates along the path being t e s t e d .…”

“…This section will discuss assumptions (3), ( 4 ) , and (5) which deal with compound predicates , adjacent domains which compute the same function , and non linear borders , respect ively . The treatment of these cases will c ertainl y require additional test points , and in some instances will demand extra processing which may render this testing approach impractical.…”

Performance Evaluation of High-Level Language Systems

“…of relative frequencies of features of source programs, rather than frequencies of events at execution time. There have been several more studies of this type (see [16]); as a rule they are of little interest to the subject of execution-time performance. However, many of the measurements reported by Knuth could have been extended to dynamic measurements; they were not, apparently only for lack of time.…”