Modular Language Research Articles

The Fortran programming language

Fortran has been in use for some 25 years, and has remained the most widely used programming language in spite of challenges from many new arrivals in the field. An official American National Standard for the language was adopted in 1966 and revised in 1978.The 1978 Fortran standard, known as Fortran 77, introduced "structured" branching, replaced Hollerith with a character-string data type, changed the minimum trip-count for the DO loop to zero, and established compromise forms for many of the variants that had developed since 1966. Compilers for this current standard version of Fortran became widely available in 1980 and 1981. Fortran 77 will remain in wide use through the decade of the 1980's.Looking toward the 1990's, efforts are now under way to modernize and further extend the Fortran language. A significant part of this modernization consists of removing (to a "Fortran 77 Compatibility Module"), and replacing with modern equivalents, many of the old features such as: arithmetic IF; assigned and computed GO TO; statement functions; DIMENSION declarations; ENTRY and alternate return features; and the label-delimited looping construct. An optional replacement for the punched-card oriented source program form will also become available.Features to be added in the Fortran of the 1990's include: whole-array expressions and assignment; precision specification for REAL data; inhomogeneous data structures; and a CASE control structure. A modular language architecture is contemplated, which will facilitate adding major extensions to the language in special application areas.

A VLSI Architecture for Software Structure: The Intel 8086

By supporting modular programs and high-level languages, this microprocessor architecture aids the implementation of complex software.

A General-Purpose System for Data Acquisition and Instrument Control

Sophisticated laboratory equipment, ground-based instruments and scientific instruments produced for space flight require ground support equipment (GSE) systems for instrument checkout and data analysis. The increasing complexity of flight instruments and the short time scales proposed for Shuttle instrument development, integration and flight require a fresh approach to instrument GSE systems design. Several groups throughout NASA have proposed that the GSE system should accompany each flight instrument throughout its life as an instrument specific integration support, control center support, and post-launch quick-look data analysis system. Such a system has been developed at the Laboratory for High Energy Astrophysics of the Goddard Space Flight Center. It consists of a minicomputer system with a modular hardware interface and a standardized modular software system and console language which are easily adaptable to a wide range of flight instruments. This paper relates thehistory of that effort, states the basic objectives of the system and describes the hardware and software which were developed to meet these objectives. The Experiment Command Interactive Language (ECIL) used to configure and control the instrument is described, and an example is given of its use.