摘要:

AbstractThe Sprite operating system allows executing processes to be moved between hosts at any time. We use this process migration mechanism to offload work onto idle machines, and also to evict migrated processes when idle workstations are reclaimed by their owners. Sprite's migration mechanism provides a high degree of transparency both for migrated processes and for users. Idle machines are identified, and eviction is invoked, automatically by daemon processes. On Sprite it takes up to a few hundred milliseconds on SPARCstation 1 workstations to perform a remote exec, whereas evictions typically occur in a few seconds. The pmake program uses remote invocation to invoke tasks concurrently. Compilations commonly obtain speed‐up factors in the range of three to six; they are limited primarily by contention for centralized resources such as file servers. CPU‐bound tasks such as simulations can make more effective use of idle hosts, obtaining as much as eight‐fold speed‐up over a period of hours. Process migration has been in regular service for over tw

ISSN:0038-0644    

DOI:10.1002/spe.4380210802

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractRegular expressions are used in many applications to specify patterns because any regular expression can be compiled into a very efficient one‐pass pattern matcher called a finite automaton. Finding matches is useful, but even more useful is parse extraction, which describes in detail how a pattern matches some input. After matching an address, for example, parse extraction makes it easy to find out the Zip code part of the address. We present an elegant, efficient algorithm for extracting a parse after matching with a finite automaton. In addition, we extend the regular expression language to include new operators for matching arbitrary left context and single character right context. The extended language can be matched as efficiently as the usual regular expression language, but is more expressive. Finally, we suggest how to apply the matching algorithms to match regular expressions containing arbitrary right context and single character left context. In effect, this allows one to specify patterns that seem to require an unlimited amount of look‐ahead to ma

ISSN:0038-0644    

DOI:10.1002/spe.4380210803

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractTLex is a pattern matching and parsing library for C++. In comparison to existing pattern matching tools, TLex sets a new standard for expressiveness when nearly optimal speed is required. It incorporates recent advances in regular expression technology that make it easier to write patterns and extract information from a successful match. An overview of TLex is presented, the pattern and parsing languages are described, and actual results of its use are discussed.

ISSN:0038-0644    

DOI:10.1002/spe.4380210804

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe PROTOB object‐oriented methodology for the executable specification of large‐scale event‐driven systems is introduced and described. Two supporting features of PROTOB are also presented: the graphic and textual language that formally describes the behaviour of objects, which is based on high‐level Petri nets called “PROT nets” and which is demonstrated to be more powerful than SA/RT dataflows; and a CASE environment with tools for specification, modelling, simulation and prototyping. Use of PROTOB is illustrated by discussion of the automated generation of distributed systems running on a network of VMS and UNI

ISSN:0038-0644    

DOI:10.1002/spe.4380210805

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractIn this paper, a methodology for constructing hierarchical and structured predicate transition net specifications is developed, which includes new systematic notation extensions for supporting various transformation techniques upon predicate transition nets and several rules for applying such transformation techniques. The levelling technique in data‐flow diagrams is adapted in the refinement and the abstraction techniques, and the state decomposition idea in state‐charts is employed in designing various label formulation operators. The methodology is illustrated through the specification of a lift system. The methodology can significantly reduce the constructing complexity and enhance the comprehensibility of large predicate transition net specificati

ISSN:0038-0644    

DOI:10.1002/spe.4380210806

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractAn efficient method for simulating instruction sets is described. The method allows for compiled instruction set simulation using the macro expansion capabilities found in many languages. Additionally, we show how the semantics of the C case statement allows instruction branching to be incorporated in an efficient manner. The method is compared with conventional interpreted techniques and is shown to offer considerable performance benefits.

ISSN:0038-0644    

DOI:10.1002/spe.4380210807

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

ISSN:0038-0644    

DOI:10.1002/spe.4380210801

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY