摘要:

AbstractUtility programs discussed in this paper were initially developed to automate the ‘drawing’ of the non‐binary trees which occur when using a Jackson type methodology for program design; these trees represent either data structures or program structures, showing the selective, sequential and iterative relationships between nodesFirst a language was developed to allow information about tree structures to be input to the programs. Techniques and algorithms are described which enabled utility programs to be coded to process this data; transforming it into printable diagrammatic representation of trees; pseudo‐code representation of program trees; and PL/I or Cobol programsSecondly a merge operation for trees had to be defined, reflecting the step in Warmer's and Jackson's methodologies of combining data tree structures together to provide a program structure. Further algorithms are described which enable this step to be performed automatically, they include checks that each particular merge can be performedBecause the aims and concepts have been fluid some of the ideas have been discarded, and programs have been rewritten. Valuable insights were gained from persuing both the rejected and the acceptable ideas, these are described in thi

ISSN:0038-0644    

DOI:10.1002/spe.4380140902

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractThis paper describes an electronic mail system which has been implemented to provide facilities for the receiver as well as the sender of electronic mail. As well as the usual mail creation, transmission and filing operations, the system allows the receiver to specify automatic redirection of mail, and provides classification facilities so that the order of mail presentation is under the receiver's control. The system also includes an automatic mechanism for acknowledging mail and for cancelling mail which is either out‐of‐date or which was sent in error. The model on which the system is based is a non‐automated office, so analogues of waste paper baskets, etc. are pro

ISSN:0038-0644    

DOI:10.1002/spe.4380140903

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractThe designer of a concurrency control is currently faced with a confusing situation: there has been a proliferation of proposed methods (in fact, it will be shown here that even in the ‘simple’ centralized case there are infinitely many methods), and although there has been some analysis of a few alternative methods using simulation and analytic models, it is usually impossible to accurately predict some of the parameters required by these models prior to the development of a system. Furthermore, over the lifetime of a system some parameters will change, possibly radically, due to changes in system usage, the replacement or addition of processors, memories, and I/O devices, the development of new applications, etc. Here, a practical approach to this problem is presented: separating policy from correctness in the design of the concurrency control. This technique was successfully used in the development of a transaction processing system for the Cm* multi‐microprocessor. As an illustration of this approach, the design of the concurrency control of this system is described in detail. This design should apply directly to any centralized single‐level (non‐hierarchical) concurrenc

ISSN:0038-0644    

DOI:10.1002/spe.4380140904

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractA software simulator can be built to facilitate debugging and testing of real‐time programs. This paper describes a simulator designed to operate in three modes: simulation, debugging and process monitoring. In the simulation mode, it simulates a Z80‐based microcomputer and can be used to execute programs written in the Z80‐assembler language. In the debugging mode, it provides facilities for interactive debugging on the instruction level. The simulator's unique feature is the process monitoring mode. It displays the activities among processes being executed concurrently under the control of a real‐time executive and thus allowing direct observation of dynamic program behaviour at the proces

ISSN:0038-0644    

DOI:10.1002/spe.4380140905

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractEmerging peephole optimizers can relieve code generators of much case analysis, but delaying code generation decisions requires register allocation algorithms that accept object code instead of the more usual intermediate code. This paper describes two programs that implement such algorithms for a retargetable optimizing compiler. In a machine‐independent fashion, they allocate and assign registers, eliminate common subexpressions (including often‐missed machine‐specific ones), identify dead variables, and define windows for the companion peephole optimizer. Their techniques for handling machine‐specific data should generalize to other optimizations

ISSN:0038-0644    

DOI:10.1002/spe.4380140906

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractWith the aid of the EM (encoding machine) compiler tool kit, a preliminary version of a scalar C compiler was implemented on the Cyber 205 in a relatively short period of time. This C compiler emphasizes functionality more than efficiency. Several benchmark programs were used to measure the performance and to compare it with an equivalent C compiler for the VAX/UNIX system. In order to make it a production‐quality C compiler, further enhancements will be necessary. This paper presents some motivating factors, implementation details, and proposes further work on developing the Cyber 205 C compile

ISSN:0038-0644    

DOI:10.1002/spe.4380140907

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractThe nature of a transducer is shown to be a mapping between representations (internal and external), analogous to the mapping between internal representations provided by typeconversion. Examples of this idea are given through programs in Ada and Modula.

ISSN:0038-0644    

DOI:10.1002/spe.4380140908

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

摘要:

AbstractThis paper describes several years' practical experience with remote procedure calls as a primary tool for application software in a large and complex distributed real‐time process control system. We motivate the use of remote procedure calls as an effective technique for the use of local area networks, describe our implementation and discuss its advantages and disadvantage

ISSN:0038-0644    

DOI:10.1002/spe.4380140909

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY

ISSN:0038-0644    

DOI:10.1002/spe.4380140901

出版商:John Wiley&Sons, Ltd.    

年代:1984

数据来源: WILEY