Self-timing programs and the quantum scheduler
Using an internally generated program clock in conjunction with a quantum scheduler creates self-timing programs that are useful in building deterministic computer systems.
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Garbarge collection for Prolog based on WAM
The Warren abstract machine (WAM) has become a generally accepted standard Prolog implementation technique. Garbage collection is an important aspect in the implementation of any Prolog system. A synopsis of the WAM is presented and then marking and compaction algorithms are shown that take advantage of WAM's unique use of the data areas. Marking and compaction are performed on both the heap and the trail; both use pointer reversal techniques, which obviate the need for extra stack space. However, two bits for every pointer on the heap are reserved for the garbage collection algorithm. The algorithm can work on segments of the heap, which may lead to a significant reduction of the total garbage collection time. The time of the algorithms are linear in the size of the areas.
MIS careers—a theoretical perspective
MIS personnel historically have exhibited a disturbingly high rate of turnover, and the job of the MIS manager is increasingly oriented to personnel and staffing problems. The MIS careers literature consistently suggests that what is needed to improve this situation is (1) more attention to formal career planning, and (2) the implementation of a dual career ladder system within the DP/IS organization. A look at the broader literature on organizational careers suggests that these suggestions may not in fact make sense. By considering only a subset of the relevant concepts about careers, we have reached conclusions that are quite possibly erroneous, and have made suggestions that will not likely help. Until further research on MIS personnel and their career needs is accomplished, we will have no valid basis for prescribing solutions to MIS careers problems. Suggestions for needed research are outlined.
Factors of success for end-user computing
A two-phase study concerned with the factors of success associated with the development of computer applications by end users was conducted in 10 large organizations. During the first phase, in-depth interviews were used to refine a preliminary model of the factors of success for user development of computer applications (UDA). In the second phase, a questionnaire was administered to 272 end users experienced in developing applications. Statistical tests of the relationships in the model indicated that all but one of the derived hypotheses were substantiated. The result of this study is a field-verified model of the factors of success of UDA that provides a basis for implementation of UDA practices and policies in organizations, as well as for further research in end-user computing.
Information technology and dataveillance
Data surveillance is now supplanting conventional surveillance techniques. With this trend come new monitoring methods such as personal dataveillance and mass dataveillance that require more effective safeguards and a formal policy framework.
The world’s fastest Scrabble program
An efficient backtracking algorithm makes possible a very fast program to play the SCRABBLE® Brand Crossword Game. The efficiency is achieved by creating data structures before the backtracking search begins that serve both to focus the search and to make each step of the search fast.
The higraph, a general kind of diagramming object, forms a visual formalism of topological nature. Higraphs are suited for a wide array of applications to databases, knowledge representation, and, most notably, the behavioral specification of complex concurrent systems using the higraph-based language of statecharts.
Growth stages of end user computing
The stages of growth and interconnectedness of the applications of end user computing are described in a model that is directed toward management and planning.
An astronomer-turned-sleuth traces a German trespasser on our military networks, who slipped through operating system security holes and browsed through sensitive databases. Was it espionage?
Managing prototype knowledge/expert system projects
Computer science technology in the 1990s will involve knowledge/expert systems. Fundamental issues of technology transfer, training, problem selection, staffing, corporate politics, and more, are explored.
Reasoning with worlds and truth maintenance in a knowledge-based programming environment
In traditional knowledge-based system development environments, the fundamental representational building blocks are mechanisms such as frames, rules, and attached procedures. The KEE system has been extended to include both a context (worlds) system and a truth maintenance system.
Cost/benefit analysis for incorporating human factors in the software lifecycle
New software engineering techniques and the necessity to improve the user interface in increasingly interactive software environments have led to a change in traditional software development methods. Methodologies for improvement of the interface design, an overview of the human factors element, and cost/benefit aspects are explored.
Relational database design using an object-oriented methodology
Of the many approaches to relational database design, the Object Modeling Technique (OMT) is particularly effective. A comprehensive explanation and two applications show the semantic improvement of OMT over other approaches.
Distributed programming in Argus
Argus—a programming language and system developed to support the implementation and execution of distributed programs—provides mechanisms that help programmers cope with the special problems that arise in distributed programs, such as network partitions and crashes of remote nodes.
Special section on operating systems
This special collection of articles examines recent research in operating systems, focusing on particular systems and projects that are seminal and representative. The areas these articles cover include distributed operating systems, heterogeneous computer systems, distributed programming, and real-time systems.
The V distributed System was developed at Stanford University as part of a research project to explore issues in distributed systems. Aspects of the design suggest important directions for the design of future operating systems and communication systems.
Interconnecting heterogeneous computer systems
A software structure created by the Heterogeneous Computer Systems (HCS) Project at the University of Washington was designed to address the problems of heterogeneity that typically arise in research computing environments.
Self-assessment procedure XVIII: fundamentals of data communications
A self-assessment procedure dealing with the fundamentals of data communications
The Cedar File System (CFS) is a workstation file system that provides access to both a workstation's local disk and to remote file servers via a single hierarchical name space. CFS supports a group of cooperating programmers by allowing them to both manage local naming environments and to share consistent versions of collections of software.
We present a novel, yet straightforward linear-time algorithm for merging two sorted lists in a fixed amount of additional space. Constant of proportionality estimates and empirical testing reveal that this procedure is reasonably competitive with merge routines free to squander unbounded additional memory, making it particularly attractive whenever space is a critical resource.
On synchronization in hard-real-time systems
The design of software for hard-real-time systems is usually difficult to change because of the constraints imposed by the need to meet absolute real-time deadlines on processors with limited capacity. Nevertheless, a new approach involving a trio of ideas appears to be helpful for those who build software for such complex applications.
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