Methods for Performance Evaluation of Parallel Computer Systems

Although parallel computers have existed for many years, recently there has been a surge of academic, industrial and governmental interest in parallel computing. Commercially manufactured parallel computers have started to become available. Many new experimental parallel architectures are reported in the literature every year. Software for many types of applications, from scientific number crunching to artificial intelligence, is being written to run on parallel machines. Performance is an essential consideration both in the design of new systems and the deployment of existing systems. Users of computers wish to utilize their hardware and software systems as efficiently as possible. Over the years, a field known as computer performance evaluation has arisen to address the problem of quantifying and predicting computer performance. Methods exist that can determine how efficiently a system's resources are being used. These can help track down the probable causes of performance problems

HAL/S-FC compiler system functional specification

The functional requirements to be met by the HAL/S-FC compiler, and the hardware and software compatibilities between the compiler system and the environment in which it operates are defined. Associated runtime facilities and the interface with the Software Development Laboratory are specified. The construction of the HAL/S-FC system as functionally separate units and the interfaces between those units is described. An overview of the system's capabilities is presented and the hardware/operating system requirements are specified. The computer-dependent aspects of the HAL/S-FC are also specified. Compiler directives are included

Logic, parallelism and semantic networks : the binary predicate execution model

This thesis develops the Binary Predicate Execution Model; a distributed, massively-parallel system for semantic networks and knowledge bases that is built on a subset of first-order predicate logic. The use of logic gives the model an easily-understood programming paradigm and a well-defined semantics of execution. When expressed in binary predicates, a simple graphical interpretation can be used. All program facts are represented in an assertion graph. Each vertex is associated with a term appearing in a fact and the edges are labeled with the predicate names. Similar graphs are also associated with each rule body and the query. Finding all possible solutions corresponds to finding all possible matches between the query graph and the assertion graph. Invoking a rule corresponds to substituting the graph of its body constrained by the dependencies between its arguments. This can be implemented in a parallel, message-passing fashion where the assertion graph vertices are active processing elements which asynchronously exchange messages identifying different parts of the query that remain to be matched and containing any binding information from previous matching required to accomplish this. The model is data-driven since every message can be immediately processed without the need for any centralized control or centralized memory. By restricting how functional terms can occur, distributed data structures and remote data look-ups for unification are eliminated. Thus, the model's performance on increasingly larger problems scales-up given increasingly larger machines in most cases. Architectural support for the model is investigated and simulation results of a relatively simple software implementation are reported. This suggests performance on the order of 10^5 logical inferences per second for 256 processing elements in an n-cube configuration. Further research directions, including that of increasing efficiency, are discussed

Proceedings of the NSSDC Conference on Mass Storage Systems and Technologies for Space and Earth Science Applications

The proceedings of the National Space Science Data Center Conference on Mass Storage Systems and Technologies for Space and Earth Science Applications held July 23 through 25, 1991 at the NASA/Goddard Space Flight Center are presented. The program includes a keynote address, invited technical papers, and selected technical presentations to provide a broad forum for the discussion of a number of important issues in the field of mass storage systems. Topics include magnetic disk and tape technologies, optical disk and tape, software storage and file management systems, and experiences with the use of a large, distributed storage system. The technical presentations describe integrated mass storage systems that are expected to be available commercially. Also included is a series of presentations from Federal Government organizations and research institutions covering their mass storage requirements for the 1990's