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Applications Programming, Backlog, Applications Backlog, Prototype, Methods, Information Systems, System Design, and Models

A prototyping development method is presented here which has the potential to reduce the growing application development backlog. Prior research and our findings indicate that a prototyping process can assist in the efficient development of application systems by breaking a complex problem into several comprehensive parts. A state-transition model of the IS development process is presented and discussed. A two-prototype method is explained in the context of this model. Two projects are described which are typical of development efforts made by end users in a microcomputer environment and IS specialists in a mainframe environement. (Reprinted by Permission of Publisher.)

Software, Process Control, Real-Time System, Software Engineering, Application Development Software, Programming, Prototype, Requirements Analysis, and System Development

Large-scale software requires effective management for production. Such large-scale software consists of application software, a utility subsystem, and an operating system. Individual software factories require levels of abstraction in a design process which uses prototyping, reusing, and program generating systems. The first level is the requirements level which defines the external devices with which the software communicates. A capsulated form of a requirements description is shown. The data-function or design level is the transition, the definition of a user's needs and the establishment of the model. Program models are defined and implemented in the program level. Prototyping is done throughout the entire process for the first operational versions of software interfaces. Productivity and reliability are the most crucial factors in management of a software factory. In addition to the encapsulated format examples, numerous block diagrams illustrate software production and the rolling mill software production example.

Prototype, Specifications, Performance Specifications, Software Engineering, Program Development Techniques, and Comparative Study

There has been much discussion on the relative merits of the specification-driven approach to software development versus the prototyping approach. An experiment has been conducted to give some basis for comparison of the two approaches. Seven software teams developed the same application software product. Three used the prototyping approach, four the specifying approach. Results indicate that prototyping required less effort and less code for equivalent performance. Prototyped products were easier to learn and use but rated lower on functionality and robustness. Specified products were easier to integrate.

Software Engineering, Software Design, System Development, Requirements Analysis, Specifications, Methods, Software Maintenance, Software Metrics, and Software Quality

Software engineering seeks to devise techniques for software development. Software systems go through two principal phases: development, and operations and maintenance. The conventional design-scheme requires that a large amount of time be spent developing specifications. Alternative schemes, include rapid prototyping, the very high level language approach, and the reusability approach. The design phase includes the decomposition of the requirement specification into certain basic elements and partitioning the set of decomposed elements into modules. Current design methodologies include functional decomposition, the data-flow design, and the data-structure design. Software maintenance can be divided into three categories: perfective, adaptive, and corrective maintenance. Software quality assurance aims to optimize reliability, reusability, and efficiency. Tables, graphs, and diagrams illustrate many of the features of software engineering.

Programming, Programming Language, Software Engineering, Methods, and I/O Management

Responding to a letter from Robert Baber (Computer, June 1985, p. 112), a reader disagrees with the conclusion that I-O is a conceptual block which hampers software development and argues instead that it is the central concept of intelligible programs. Current programming languages are certainly inadequate, in that they confuse design with implementation. These separate concerns should be dealt with in separate languages, and separate prototyping notions for designer and user should be added. Thus interprocess communication is a vital concept, of which I-O is the simplest expression.

Programming Language, Expert Systems, Software Design, Evaluation, System Design, Application Development Software, and Small-X (Program development software)

Small-X is a programming language designed for building expert systems that is not for the computer novice. A Small-X program consists of statements called rules. The language provides two key features that distinguish it from other languages: a set of pattern-matching and evaluation functions, and the automatic handling of control flow. Small-X also has good debug features that allow users to trace rules. The manual for Small-X is complete and well-written. The language serves as a tool for learning about expert systems and for prototyping trial applications, but it is not the most trustworthy of program development systems.

Programming Language, Programming, Scientific Research, and Mathematical Programming

We describe linear future semantics, an extension of linear history semantics as introduced by Francez, Lehmann, and Pnueli, and show how it can be used to add multiprocessing to languages given by standard continuation semantics. We then demonstrate how the resulting semantics can be implemented. The implementation uses functional abstractions and non-determinacy to represent the sets of answers in the semantics. We give an example, using a semantic prototyping system based on the language Scheme. (Reprinted by permission of the publisher.)

Programming Language, PROLOG, Compiler/decompiler, and Algorithm

The use of Prolog as a language offers advantages for describing succinctly most of the algorithms needed in prototyping and implementing compilers, or producing tools that facilitate the task of compiling. One approach in implementing compilers using Prolog consists of coupling actions to recursive descent parsers to produce syntax-trees, which are utilized in guiding the generation of assembly code. Prolog is not only used in parsing and compiling, but is a labor-saving device in prototyping and implementing many non-numerical algorithms which arise in compiling. Unification and nondeterminism as means to circumvent costly unnecessary features are also discussed. Other topics include: bottom-up and top-down parsers; syntax-directed translation; grammar properties; code generation; and newly proposed features for compiler construction.

Prototype, New Technique, Application Development Software, Object-Oriented Languages, Smalltalk (Computer program language), Software Design, and Software Engineering

The Smalltalk object-oriented programming language developed at the Xerox Palo Alto Research Center in the early 1970s offers a completely new environment for software development. Smalltalk is not easy to learn, even for programmers with experience in standard languages. Excellent references to Smalltalk are the Blue Book and the Orange Book: the Blue Book deals mainly with features of the language, while the Orange Book deals with the environment. Learning the language poses a short-term disadvantage, but the long-term gains in productivity may be worth the initial investment. Commercial versions of Smalltalk are available on workstations like the Tektronix 440X series, the Sun, and the IBM PC AT; implementations for the MicroVAX are under development.

System Development, Comparative Study, System Design, Design, Methods, Project Management Software, Requirements Analysis, Research and Development, and Prototype

This article presents a retrospective comparative study of the use of the system development life cycle (SDLC) and prototyping methods to help select a development approach for a given information systems (IS) project. The respondents were asked (a) to decide independently whether one of their recent IS projects was developed using either the SDLC or prototyping approach and if so, (b) to evaluate the merit of that approach in terms of ease of project management, project requirements, project characteristics, impact on decision making, and user and designer satisfaction. The results indicate: (1.) Design methods cannot be considered apart from project, environment and decision characteristics. (2.) A clear cut preference of one method over the other could not be established. Each method performed better in some areas that in others. (3.) A framework that can be used by a project director for selecting a design method to develop a system could be postulated. (Reprinted with permission of the publisher.)

Application Development Software, Prototype, and Programming

Logic programming has great potential for reducing the cost of software development. We argue that, with an appropriate programming methodology, a logic programming system provides a powerful tool for rapid software prototyping. It is sufficiently formal and high-level to allow reasoning about specifications, and it provides an immediate operational validation of the programmer's intuitions. The methodology is introduced by means of an example larger than those usually used to illustrate the advantages of logic programming. We start with an informal specification of a structure-editor, show how it is formalized into a directly executable prototype, and introduce guidelines for validating logic programming code as implemented in Prolog. The developed prototype can be used for a number of applications: syntax-directed editor, semantic network browser, etc. The editor is compact but readable, and is quite efficient. (Reprinted by permission of the publisher.)

Power Systems, Artificial Intelligence, and Energy Management

Designers of Energy Management Systems (EMS) use Artificial Intelligence (AI) to solve diagnosis and decision problems making EMS more useful. The use of AI in EMS is explained, and differences between knowledge-based expert systems and traditional numeric algorithm development are examined. The differences between expert systems and the numeric approach are illustrated with a relay fault diagnosis system, demonstrating both the traditional and rapid prototyping approaches to its development. AI implementation in EMS and potential AI applications to power system operations are explored.

Semantics, Programming Language, Graph Theory, Hardware Description Language, and Artificial Intelligence

Systems semantics is a concept which extends programming languages' denotational semantics into a semantics for describing arbitrary systems. The arbitrary systems include objects that are in no sense computations. Two classes of applications are discussed: unidirectional systems and nonunidirectional systems. A brief discussion is also included of implementation and rapid prototyping strategies in various system description environments.

Software Packages, Documentation, Text Processing Software, Technical Writing, User-Written Software, Electronic Publishing Industry, and Symbolics Inc.

Concordia is designed as a development environment for technical writers. From Symbolics, Concordia is an extension of Genera, the software development environment for Symbolics computers. Concordia has specialized support of the different phases of a document life cycle: writing, editing illustration, design, production, and maintenance. Concordia is part of the Symbolics documentation system, where the central component is the document database. It is a framework organizing the tasks and activities in the document life cycle, with three main subactivities: text editing, graphic editing, and previewing. Concordia provides a number of ways of looking at a document, including: seeing the reader's viewpoint (WYSIWYG), local hardcopy, preview, and final hardcopy. The approach has been particularly successful in the areas of fast prototyping, on-line delivery, quality enhancement, and maintenance.

Information Systems, Decision Support Software, Operations Research, Technology, New Technique, Maintenance, Support Services, Systems Analysis, and System Design

It is shown that systems maintenance activity in large information systems would benefit greatly if the process knowledge reflecting the teleology of a design could be captured. It could be used to anticipate the consequences of changing conditions or requirements. Representation and Maintenance of Process knowledge (REMAP) is a formalism that accumulates design process knowledge to manage systems evolution. REMAP acquires and maintains dependencies among the design decisions made during a prototyping process and learns general domain-specific design rules on which the dependencies are based. The knowledge is applicable to prototype refinement, systems maintenance, and the reuse of existing design or software fragments to construct similar ones with analogical reasoning techniques.

Prototype, New Technique, Utilization, Functional Capabilities, Computer-Aided Software Engineering, and Cost Benefit Analysis

Computer-aided software prototyping from specifications and reusable components is a viable strategy for improving programming productivity, and such a system is described. The system uses the powerful and easy-to-use PSDL prototype system description (specification) language and a set of software tools. PSDL provides a computational model that integrates dataflow, unified non-procedural controls, and timing. The tools include an execution support system, a rewrite system for reducing variations explicit from the specifications, a syntax-directed editor with graphics tools, a software base of reusable components, a design database, and a program design management system for organizing, retrieving, and effecting reusable components as well as controlling versions, alternates, and refinements of the software product.

ISDN, Simulation, Prototype, ISO, and Algorithm

Veda, a simulator software tool, may be used by designers for protocol modeling and verification. It can provide rapid prototypes of distributed algorithms, and describes them using Estelle, an ISO formal description technique. Uses for Veda include: ISDN specifications; radiotelephone protocols; switching designs; satellite protocols; and remote maintenance.

Software Engineering, Modeling, Methods, Real-Time System, Process Control, and Programming Language

A language model, the Abstract Interaction Tool (AIT), is introduced for the specification of the User Interface Management Systems. It offers a tree-like hierarchy of interaction objects. Each object can be considered as an abstract input device containing a syntax-like specification of the required input pattern. The hierarchy of specifications makes up a system of syntactical productions with multiple control. The interface to the physical interaction devices is represented by the terminal nodes of the AIT. Hierarchical output resource management is featured, and at the higher, more abstract level, the input-output is loosely coupled. Coupling becomes increasingly tight at the lower levels. AITs model the functions (what) required by the user at the upper levels, but at the lower levels, the way to accomplish them (how) is emphasized. Facilities exist for context-dependent and expertise levels. Links to application modes are provided in a special section in the AIT. AITs can be applied to graphics, process control, dialogue, and real-time systems. They can also define controlled production rules in knowledge-based systems and provide tools for the software engineering phases specification and prototyping.

Adaptability, Parallel Algorithms, Program Development Techniques, Concurrent Programming, and Tuning

To facilitate extensive experimentation with program prototypes, a programming system that supports rapid prototyping of parallel programs needs to provide high-level language primitives with which programs can be explicitly, statically, or dynamically tuned with respect to performance and reliability. Language primitives and an associated programming system for tuning are described and implemented. They have been tested with various parallel applications on workstations on a UNIX network.

Strategic Planning, System Development, Optimization, Tutorial, Software Engineering, Business Planning, and Software Design

Delaying commitment to a particular software design reduces several problems resulting from premature commitment including: lack of freedom for iterative design, increased maintenance costs, increased effects of bugs, and nonportability of software. Delaying commitment provides time to search for the most effective solution and increases the opportunity to recognize it. Tactics to delay commitment to a final design include: use of modular programming, choice of parameters appropriate to a problem, keeping the problem and solution as general as possible, retain options to choose a parallel program solution, do not use prototyping tools, use abstractions, and use interfaces.