Date: Tue, 10 Dec 1996 22:56:07 GMT Server: NCSA/1.4.2 Content-type: text/html Last-modified: Wed, 02 Oct 1996 18:18:34 GMT Content-length: 6669 George Forman: Publications

George Forman: Publications

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Survey: The Challenges of Mobile Computing

with John Zahorjan.
IEEE Computer (journal), vol.27, no.4, pp.38-47, April 1994.
postscript of technical report version

Abstract: The technical challenges that mobile computing must surmount to achieve its potential are hardly trivial. Some of the challenges in designing software for mobile computing systems are quite different from those involved in the design of software for today's stationary networked systems. The authors focus on the issues pertinent to software designers without delving into the lower level details of the hardware realization of mobile computers. They look at some promising approaches under investigation and also consider their limitations. The many issues to be dealt with stem from three essential properties of mobile computing: communication, mobility, and portability. Of course, special-purpose systems may avoid some design pressures by doing without certain desirable properties. For instance portability would be less of a concern for mobile computers installed in the dashboards of cars than with hand-held mobile computers. However, the authors concentrate on the goal of large-scale, hand-held mobile computing as a way to reveal a wide assortment of issues.

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ZPL vs. HPF: A Comparison of Performance and Programming Style

with L. Snyder, R. Anderson, B. Chamberlain, S. Choi, E. Lewis, C. Lin and W. Weathersby.
Submitted for publication. postscript

Abstract: This paper compares two data parallel languages, ZPL and HPF, in terms of programming style and performance. The results show that for eight programs from a number of standard benchmark suites, ZPL generally outperforms HPF, and ZPL expresses problems at higher levels of abstraction, yielding programs that are shorter, less error prone and easier to maintain. ZPL's better performance comes from its cleaner expression of computation, from which a compiler can extract parallelism more easily.

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The Ariadne debugger: scalable application of event-based abstraction.

with J. Cuny, A. Hough, J. Kundu, C. Lin, L. Snyder, and D. Stemple.
ACM/ONR Workshop on Parallel and Distributed Debugging, San Diego, CA, USA, 17-18 June 1993.
in SIGPLAN Notices, vol.28, no.12, pp.85-95, Dec. 1993.

Abstract: Massively parallel computations are difficult to debug. Event-based behavioral abstraction provides a mechanism for managing the volume of data by allowing users to specify models of intended program behavior that are automatically compared to actual program behavior. Transformations of logical time ameliorate the difficulties of coping with asynchrony by allowing users to see behavior from a variety of temporal perspectives. Previously, we combined these features in a debugger that automatically constructed animations of user-defined abstract events in logical time. However, our debugger did not always provide sufficient feedback nor did it effectively scale up for massive parallelism. We address these problems in a new debugger, called Ariadne. Ariadne uses a simple language to specify behavioral abstractions as patterns of events in logical time. These patterns are detected in traces of program behavior by collections of small finite-state recognizers which allow substantive feedback on match failures.

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George H. Forman, gforman@hpl.hp.com
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