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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 955 records · Page 53
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

The augment precompiler as a tool for the development of special purpose arithmetic packages

A FORTRAN precompiler, AUGMENT, is used to develop packages for nonstandard arithmetics. It renders the source code more lucid, reduces the number of lines of code in a nonstandard arithmetic package, facilitates modification, and decreases the problems of transporting such a package to another host system. AUGMENT is briefly described and its use in the construction of the interval package is discussed. Other applications of AUGMENT are also included.

Crary, F. D.↗
NASA NTRS1978

Programming in HAL/S

HAL/S is a computer programming language; it is a representation for algorithms which can be interpreted by either a person or a computer. HAL/S compilers transform blocks of HAL/S code into machine language which can then be directly executed by a computer. When the machine language is executed, the algorithm specified by the HAL/S code (source) is performed. This document describes how to read and write HAL/S source.

Ryer, M. J.↗
NASA NTRS1980

FAME, a microprocessor based front-end analysis and modeling environment

Higher order software (HOS) is a methodology for the specification and verification of large scale, complex, real time systems. The HOS methodology was implemented as FAME (front end analysis and modeling environment), a microprocessor based system for interactively developing, analyzing, and displaying system models in a low cost user-friendly environment. The nature of the model is such that when completed it can be the basis for projection to a variety of forms such as structured design diagrams, Petri-nets, data flow diagrams, and PSL/PSA source code. The user's interface with the analyzer is easily recognized by any current user of a structured modeling approach; therefore extensive training is unnecessary. Furthermore, when all the system capabilities are used one can check on proper usage of data types, functions, and control structures thereby adding a new dimension to the design process that will lead to better and more easily verified software designs.

Rosenbaum, J. D.↗
NASA NTRS1980

Implementing the UCSD PASCAL system on the MODCOMP computer

The implementation of an interactive software development system (UCSD PASCAL) on the MODCOMP computer is discussed. The development of an interpreter for the MODCOMP II and the MODCOMP IV computers, written in MODCOMP II assembly language, is described. The complete Pascal programming system was run successfully on a MODCOMP II and MODCOMP IV under both the MAX II/III and MAX IV operating systems. The source code for an 8080 microcomputer version of the interpreter was used as the design for the MODCOMP interpreter. A mapping of the functions within the 8080 interpreter into MODCOMP II assembly language was the method used to code the interpreter.

Wolfe, T.↗
NASA NTRS1981

Description of a digital computer simulation of an Annular Momentum Control Device (AMCD) laboratory test model

A description of a digital computer simulation of an Annular Momentum Control Device (AMCD) laboratory model is presented. The AMCD is a momentum exchange device which is under development as an advanced control effector for spacecraft attitude control systems. The digital computer simulation of this device incorporates the following models: six degree of freedom rigid body dynamics; rim warp; controller dynamics; nonlinear distributed element axial bearings; as well as power driver and power supply current limits. An annotated FORTRAN IV source code listing of the computer program is included.

Woolley, C. T.↗
NASA NTRS1981

A computer simulation of the transient response of a 4 cylinder Stirling engine with burner and air preheater in a vehicle

A series of computer programs are presented with full documentation which simulate the transient behavior of a modern 4 cylinder Siemens arrangement Stirling engine with burner and air preheater. Cold start, cranking, idling, acceleration through 3 gear changes and steady speed operation are simulated. Sample results and complete operating instructions are given. A full source code listing of all programs are included.

Martini, W. R.↗
NASA NTRS1981

Coal conversion systems design and process modeling. Volume 2: Installation of MPPM on the Signal 9 computer

Relevant differences between the MPPM resident IBM 370computer and the NASA Sigma 9 computer are described as well as the MPPM system itself and its development. Problems encountered and solutions used to overcome these difficulties during installation of the MPPM system at MSFC are discussed. Remaining work on the installation effort is summarized. The relevant hardware features incorporated in the program are described and their implications on the transportability of the MPPM source code are examined.

Source record↗
NASA NTRS1981

Computerized symbolic manipulation in nonlinear finite element analysis

The potential of using computerized symbolic manipulation in the development of nonlinear finite elements is discussed. Three tasks which can be efficiently performed using computerized symbolic manipulation are identified: (1) generation of algebraic expressions for the stiffness coefficients of nonlinear finite elements, (2) generation of FORTRAN source code for numerical evaluation of stiffness coefficients, and (3) checking the correctness of the FORTRAN statements for the arrays of coefficients. The symbolic and algebraic manipulation system MACSYMA is used in the present study. Two sample MACSYMA programs are presented for the development of the nonlinear stiffness coefficients of two-dimensional, shear-flexible, doubly-curved deep shell elements. The first program is for displacement models and the second program is for mixed models with discontinuous stress-resultant fields at interelement boundaries.

Noor, A. K.↗
NASA NTRS1983

Text File Comparator

File Comparator program IFCOMP, is text file comparator for IBM OS/VScompatable systems. IFCOMP accepts as input two text files and produces listing of differences in pseudo-update form. IFCOMP is very useful in monitoring changes made to software at the source code level.

Kotler, R. S.↗
NASA NTRS1982

An Automated FORTRAN documenter

A set of programs designed to help R&D programmers document their FORTRAN programs more effectively were written. The central program reads FORTRAN source code and asks the programmer questions about things it has not heard of before. It inserts the answers to these questions as comments into the FORTRAN code. The comments, as well as extensive cross-reference information, are also written to an unformatted file. Other programs read this file to produce printed information or to act as an interactive document.

Erickson, T.↗
NASA NTRS1982

Automated verification of flight software. User's manual

(Automated Verification of Flight Software), a collection of tools for analyzing source programs written in FORTRAN and AED is documented. The quality and the reliability of flight software are improved by: (1) indented listings of source programs, (2) static analysis to detect inconsistencies in the use of variables and parameters, (3) automated documentation, (4) instrumentation of source code, (5) retesting guidance, (6) analysis of assertions, (7) symbolic execution, (8) generation of verification conditions, and (9) simplification of verification conditions. Use of AVFS in the verification of flight software is described.

Saib, S. H.↗
NASA NTRS1984

Least-Squares Prediction of Solar Activity

Studies of statistical methods for predicting future solar activity described in report containing extensive graphical and tabular presentations of analyses. Lagrangian-least-squares method, which gives best predictions presented in detail. FORTRAN source code for method given.

Holland, R. L.↗
NASA NTRS1983

Logic Simulator Program

The source code for the SPICE 2 program was deblocked in order to isolate and compile the subroutine in an effort to provide a software simulation of discrete and combinatorial electronic components. Incompatibilities between the UNIVAC 1180 FORTRAN and the Sigma V CP-V FORTRAN 4 were resolved. The SPICE 2 model is to be used to determine gate and fan-out delays, logic state conditions, and signal race conditions for transistor array elements and circuit logic to be patterned in the (SPI) 7101 CMOS silicon gate semicustom array. The simulator is to be operable from the CP-V time sharing terminals.

Agarwal, R. K.↗
NASA NTRS1984

HYTESS: A hypothetical turbofan engine simplified simulation

A users manual for a hypothetical turbofan engine simplified simulation is presented. This digital simulation exists as FORTRAN source code. The program is self-contained and was developed to offer those interested in engine dynamics and controls research an efficient, realistic, and easily used engine simulation. The engine is modeled using a state space formulation. Matrix elements within the linear state space structure are nonlinear functions of various engine variables.

Merrill, W. C.↗
NASA NTRS1983

Characteristics of a prototype experiment

A new proposed software system was prototyped. Since the system, the Flight Dynamics Analysis System (FDAS), was to be a source code control system, and not the more typical flight dynamics software which NASA personnel were more familiar with, the decision was made to prototype an initial implementation in order to gain insights into the actual features needed to build a full FDAS and to evaluate the idea of prototype in NASA environment. The status of that project at the end of 1983 is described.

Sukri, J.↗
NASA NTRS1983

Testing and error analysis of a real-time controller

Inexpensive ways to organize and conduct system testing that were used on a real-time satellite network control system are outlined. This system contains roughly 50,000 lines of executable source code developed by a team of eight people. For a small investment of staff, the system was thoroughly tested, including automated regression testing, before field release. Detailed records were kept for fourteen months, during which several versions of the system were written. A separate testing group was not established, but testing itself was structured apart from the development process. The errors found during testing are examined by frequency per subsystem by size and complexity as well as by type. The code was released to the user in March, 1983. To date, only a few minor problems found with the system during its pre-service testing and user acceptance has been good.

Savolaine, C. G.↗