Metaphors of Instrumental Computer Use: A Case Study

There are two metaphors for describing instrumental computer use: the computer as a tool, and a more comprehensive package metaphor that emphasizes all aspects of computer use (hardware, software, and social interactions with vendors and other actors in the computing world). Whereas the tool view of computing is concerned with the direct costs of hardware and software, the package view helps one estimate all costs -- social and technical -- of instrumental computer use. Data from a case study of two research laboratories that used computers for data collection provides empirical support for a package metaphor

Parallel interpretation of logic programs

Logic programs offer many opportunities for parallelism. We present an abstract model that exploits the parallelism due to nondeterministic choices in a logic program. A working interpreter based on this model is described, along with variants of the basic model that are capable of exploiting other sources of parallelism. We conclude with a discussion of our plans for experimenting with the various models, plans which we hope will lead eventually to a multi-processor machine

Parallel Logic Programs on the HP Mayfly

19 pagesThe Mayfly, a parallel processor being built at HP Labs in Palo Alto, has architectural support for several import.ant. aspects of the OM virtual machine for parallel logic programs. Each node has a coprocessor that is able to relieve the main processor of a significant amount oft.he "housekeeping" work of memory management , task switching, and message handling. This paper describes how the coprocessor implements kernel level functions in OM, with particular attention to the operations that support task switching. The paper includes detailed timing data from a program with interleaved parallel threads to show that while the main processor is busy in one thread the coprocessor can effectively build the context for the next thread

Efficient Logic Programs: A Research Proposal

The goal of the proposed research is to develop methods for efficient implementation of logic programs. There are two areas we wish to investigate, both of which are continuations of research conducted by members of the UCI dataflow architecture group. One aspect of the proposed research involves development of a non-von Neumann architecture for parallel execution of logic programs; preliminary work in this area is reported by Conery [9]. The second area invovles transformation of high level logic specifications into efficient Prolog and/or procedural language programs, and is based on work by Morris [20]

Architected Failure Handling for AND-Parallel Logic Programs

14 pagesIn this paper, we present an architected approach to failure handling for independent AND parallel logic programs. That is, the architecture presented here represents its failure handling algorithm as a sequence of simple abstract machine instructions, rather than as a built-in function. Information about data dependencies is used by a compiler to generate special purpose fail routines on a clause-by-clause basis. We also present two simple optimizations that further specialize the handling of failures for each clause

Explorations in computing : an introduction to computer science and Phyton programming

xv, 422 p.; 26 c