Showing papers on "Degree of parallelism published in 1980"

Parallelism and recovery in database systems

Abstract: In this paper a new method to increase parallelism in database systems is described. Use is made of the fact that for recovery reasons, we often have two values for one object in the database—the new one and the old one. Introduced and discussed in detail is a certain scheme by which readers and writers may work simultaneously on the same object. It is proved that transactions executed according to this scheme have the correct effect; i.e., consistency is preserved. Several variations of the basic scheme which are suitable depending on the degree of parallelism required, are described.

Design of special-purpose VLSI chips: Example and opinions

Abstract: This paper identifies important steps in the design of a special purpose VLSI chip, and argues that the most crucial step is the design of the underlying algorithm. Because the algorithm determines the degree of parallelism and pipelining that is possible, it largely determines the performance of the chip. Furthermore, if the underlying algorithm has the right properties such as modularity and regularity, then the rest of the design should be routine and thus take little effort. These claims are supported by a concrete example—the design of an efficient pattern matching chip, which has been fabricated for testing.

A study in parallel rewriting systems

Abstract: In this paper we study systematically three basic classes of grammars incorporating parallel rewriting: Indian parallel grammars, Russian parallel grammars and L systems. In particular by extracting basic characteristics of these systems and combining them we introduce new classes of rewriting systems ( ETOL [ k ] systems, ETOLIP systems and ETOLRP systems) Among others, some results on the combinatorial structure of Indian parallel languages and on the combinatorial structures of the new classes of languages are proved. As far as ETOL systems are concerned we prove that every ETOL language can be generated with a fixed (equal to 8) bounded degree of parallelism.

Parallelism and Representation Problems in Distributed Systems

Abstract: A hierarchical view of program representation is used to explain the problems of matching various representations to underlying distributed architectures. If a program is to effectively use a distributed computer system, it is necessary to represent and detect a high degree of parallelism. Methods of detecting such parallelism and their limitations are discussed. The actual machine level representation of a high-level language program also affects the ability to achieve a good match between the computer system resources and the program. The concept of an ideal machine for the program leads naturally to a representation employing a directly executed language. The initial program representation profoundly influences the possibility of obtaining a good representation at other levels of the hierarchy. A poor initial language representation leads to unnecessary architectural contraints or insufficient information to efficiently execute a program. The issue of suitable initial representation for distributed hardware is approached employing a functional language basis.

Device for maintaining parallelism of cross rail of gateetype machine tool

Abstract: PURPOSE:To perform machining with high accuracy, by always accurately maintaining the degree of parallelism of a cross rail to the top of a table even if the cross rail is repeatedly moved up and down. CONSTITUTION:When a cross rail 6 is repeatedly moved up and down, the degree of parallelism of the cross rail to a table 2 falls. The fall is detected in terms of the difference between two values shown on an indication unit 36 and corresponding to the levels of the right and left ends of the cross rail 6. The end of the cross rail 6 having deviated down as to the top of the table 2 is lifted by an adjuster 37 or 38 in response to the detection of the fall so that both the indicated values coincide with each other. The cross rail 6 is thus kept parallel with the top of the table 2. This leads to plane machining with very high accuracy of micron order.