Browse Prior Art Database

Real Time Extensions to a Programming Language Shared Variable

IP.com Disclosure Number: IPCOM000086610D
Original Publication Date: 1976-Oct-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 5 page(s) / 20K

Publishing Venue

IBM

Related People

Arthur, AJ: AUTHOR

Abstract

To do a sensor-based job, over and above those requirements needed for almost any computing job, the following functions are needed: a. The ability to delay execution of subsequent statements in a program by a stated time period. b. The ability to delay execution of subsequent statements in a program until a stated event has occurred. c. The ability to execute a named program at a given time of day. d. The ability to execute a named program on occurrence of a stated event. e. The ability to read/write data to/from sensor I/O devices. f. The ability to coordinate the activities of a suite of programs.

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Real Time Extensions to a Programming Language Shared Variable

To do a sensor-based job, over and above those requirements needed for almost any computing job, the following functions are needed: a. The ability to delay execution of subsequent statements

in a program by a stated time period.

b. The ability to delay execution of subsequent statements

in a program until a stated event has occurred.

c. The ability to execute a named program at a given time of

day.

d. The ability to execute a named program on occurrence of a

stated event.

e. The ability to read/write data to/from sensor I/O devices.

f. The ability to coordinate the activities of a suite of

programs.

Points c, d and f normally are most conveniently done by centralized facilities with the individual programs having minimum awareness of the interactions and scheduling.

It is desirable to offer these capabilities to a user of APLSV but also desirable that they are offered in a manner which is a simple, easy-to-learn, easy-to-use, natural extension of current APLSV. Such extensions must recognize the limitations of the underlying philosophy of APLSV so as not to confuse and confound users. An understanding of APLSV may be had by reference to: APL/360 User's Manual, IBM Publication GH20-0906.

APL Shared Variables User's Guide, IBM Publication SH20-1460.

APL Shared Variables TSIO Program Reference Manual, IBM

Publication SH20-1463.

There are two possible user environments for these extensions, single-user APLSV and multiuser or timesharing APLSV. For the single-station APLSV user, these extensions allow programming of a real-time experiment or a dedicated real-time application as easily as programming a normal computing or data processing job in APLSV. It need only be known how to assign names to data files, sensor lists and interrupt lists. Most of the techniques used for data file names could readily be applied to sensor list and interrupt list names; i.e., reserved system names, default names and implicit names.

These extensions allow a timesharing user to design, program and execute a complete computerized laboratory experiment from his terminal and the experimental hardware with minimal interaction with the computer support staff. His only real consideration is that he must know the names they have assigned to the portion of the shared machine resources that he is allowed to use. In other words, he must know the names of the data files, sensor lists and interrupt lists assigned to him, or the system must default to certain names based on, for example, his user ID at the terminal.

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A user will be faced by limits imposed by the fact that he is coding a real-time job in a single-thread language, APLSV. These limits are basically performance and time accuracy limits and, for many users, will not impose an undue problem. An APLSV user's educational effort to learn these extensions will be minimal as each of them is an extension of a concept and syntax already in...