摘要:

AbstractDatabase management systems offer a very reliable and attractive data organization for fast and economical information storage and processing for diverse applications. It is much more important that the information should be easily accessible to users with varied backgrounds, professional as well as casual, through a suitable data sublanguage. The language adopted here (APPLE) is one such language for relational database systems and is completely nonprocedural and well suited to users with minimum or no programming background. This is supported by an access path model which permits the user to formulate completely nonprocedural queries expressed solely in terms of attribute names. The data description language (DDL) and data manipulation language (DML) features of APPLE are also discussed. The underlying relational database has been implemented with the help of the DATATRIEVE‐11 utility for record and domain definition which is available on the PDP‐11/35. The package is coded in Pascal and MACRO‐11. Further, most of the limitations of the DATATRIEVE‐11 utility have been eliminated in the interface

ISSN:0038-0644    

DOI:10.1002/spe.4380130802

出版商:John Wiley&Sons, Ltd.    

年代:1983

数据来源: WILEY

摘要:

AbstractIn modular programs, groups of routines constitute conceptual abstractions. A method for providing execution profiles for such programs is presented. The central idea is that the execution time for a routine is charged to the routines that call it. The implementation of this method by a profiler called gprof is described. The techniques used to gather the necessary information about the timing and structure of the program are given, as is the processing used to propagate routine execution times along arcs of the call graph of the program. The method for displaying the profile to the user is discussed. Experience using the profiles for hand‐tuning large programs is summarized. Additional uses for the profiles are suggeste

ISSN:0038-0644    

DOI:10.1002/spe.4380130803

出版商:John Wiley&Sons, Ltd.    

年代:1983

数据来源: WILEY

摘要:

AbstractTop‐down design and programming methods have become well established in both commercial and academic environments. However, a programmer using such methods faces a number of organizational difficulties. This paper describes a software tool, written in Pascal, which eliminates these difficulties. It allows a programmer to interactively develop programs in a top‐down fash

ISSN:0038-0644    

DOI:10.1002/spe.4380130804

出版商:John Wiley&Sons, Ltd.    

年代:1983

数据来源: WILEY

摘要:

AbstractA verification and testing environment that includes static analysis, symbolic execution, and dynamic analysis capabilities is presented. Tool integration and co‐operation are promoted through use of an intermediate program representation and a system data manager. A substantial user interface aids application of the tools. Their use is guided by a verification and testing methodology on which the system's design is based. The environment has been engineered to support the production of flight control software written in HAL/S. The environment itself is written in Pascal and is designed to be portable. Several development experiences are described. The environment demonstrates that a strong, unified verification and testing environment can be built; it serves as a basis for future investigation

ISSN:0038-0644    

DOI:10.1002/spe.4380130805

出版商:John Wiley&Sons, Ltd.    

年代:1983

数据来源: WILEY

摘要:

AbstractThe set of meanings that may be encoded in most object languages is a subset of the meanings that may be encoded in most assembly languages. Careful exploitation of this fact in the design of the SMAL assembly and object language allows the SMAL assembler itself to be used as a linkage editor, thus eliminating the need for an expensive and often misunderstood system program. The SMAL assembler is no more complex than many assemblers in common use today, nor are the relevant aspects of the SMAL language particularly unique.

ISSN:0038-0644    

DOI:10.1002/spe.4380130806

出版商:John Wiley&Sons, Ltd.    

年代:1983

数据来源: WILEY

摘要:

AbstractReal‐time computer systems can be difficult to test when their timing characteristics influence the occurrence of problems. Because of this, tools for debugging real‐time systems must account for the interference that they produce in the system they are monitoring. The debugging monitor for the Bell System 1A processor is an example of just such a tool. This paper examines the 1A processor debugging monitor, focusing on the division of the monitor into three separate devices: a hardware monitor that allows autonomous debugging; a resident monitoring program that allows debugging with a minimal interference to normal timing; and a separate mini‐computer monitor that offers extended capability at the expense of unrestricted interfe

ISSN:0038-0644    

DOI:10.1002/spe.4380130807

出版商:John Wiley&Sons, Ltd.    

年代:1983

数据来源: WILEY

摘要:

AbstractProgram optimization has received a great deal of attention for many years, which has resulted in numerous advances in compiler technology. The effectiveness of various simple optimizations has received comparably little attention during the same time period. The simplicity of most programs suggests that straightforward optimizations pay the greatest dividends. This paper describes three such optimizations suitable for one‐pass compilers. The optimizations involve expression rearrangement, instruction selection, and the use of a cache for the allocation of resources. The cost of these optimizations is low; none require major changes to the size or structure of the compiler or reduce compilation speed by more than 10%. The benefits are high; each optimization results in at least a 10% average reduction in object code size and a corresponding reduction in execution time. Examples and implementation details are also describe

ISSN:0038-0644    

DOI:10.1002/spe.4380130808

出版商:John Wiley&Sons, Ltd.    

年代:1983

数据来源: WILEY

摘要:

AbstractThis communication describes a typical application of BCPL coroutines in simplifying the implementation of a multi‐event task, together with some problems encountered. The problems fall into two major groups: those associated with the routing of operating system messages to coroutines within a task, and those connected with data shared between coroutines. General solutions are suggested to these problems, which can occur in any program employing similar structure

ISSN:0038-0644    

DOI:10.1002/spe.4380130809

出版商:John Wiley&Sons, Ltd.    

年代:1983

数据来源: WILEY

ISSN:0038-0644    

DOI:10.1002/spe.4380130810

出版商:John Wiley&Sons, Ltd.    

年代:1983

数据来源: WILEY

ISSN:0038-0644    

DOI:10.1002/spe.4380130801

出版商:John Wiley&Sons, Ltd.    

年代:1983

数据来源: WILEY