ACM SIGPLAN history of programming languages conference PL/I language summary

PL/I was developed in two distinct stages. First the language NPL was conceived by a joint user-IBM committee. IBM alone then developed PL/I by clarifying and refining the rather incomplete specification of NPL. This overview describes the major features of PL/I, and George Radin's paper makes clear the distinctions between these two languages. The characteristics of PL/I were strongly influenced by two factors; what was known (in 1964-65) about commercial, scientific, real-time and system programming applications, and the features of FORTRAN, COBOL, and ALGOL which were useful in implementing those applications. The result is a language of great expressive power, which occasionally requires the programmer to manage great complexity.