eCommons

 

Real-Time System = Discrete System + Clock Variables

Other Titles

Abstract

How can we take a programming language off the shelf and upgrade it into a real-time programming language? Programs such as device drivers and plant controllers must explicitly refer and react to time. For this purpose, a variety of language constructs-including delays, timeouts, and watchdogs-has been put forward. We advocate an alternative answer, namely, to designate certain program variables as clock variables. The value of a clock variable changes as time advances. Timing constraints can be expressed, then, by conditions on clock values. A single new language construct-the guarded wait statement-suffices to enforce the timely progress of a program. Our presentation proceeds in two steps. First, we extend untimed systems (Section 1) with clock variables (Section 2); then we introduce the guarded wait statement (Section 3). The usage of clock variables and the guarded wait statement is illustrated with real-time applications such as round-robin (timeout-driven) scheduling, priority (interrupt-driven) scheduling, and embedded process control (Section 4). Indeed, clock variables generalize naturally to variables that measure environment parameters other than time (Section 5). In keeping with an expository style, all references are clustered in bibliographic remarks at the end of each section. We conclude by pointing to selected literature on formal methods and support tools for our approach to real-time programming (Section 6).

Journal / Series

Volume & Issue

Description

Sponsorship

Date Issued

1994-01

Publisher

Cornell University

Keywords

computer science; technical report

Location

Effective Date

Expiration Date

Sector

Employer

Union

Union Local

NAICS

Number of Workers

Committee Chair

Committee Co-Chair

Committee Member

Degree Discipline

Degree Name

Degree Level

Related Version

Related DOI

Related To

Related Part

Based on Related Item

Has Other Format(s)

Part of Related Item

Related To

Related Publication(s)

Link(s) to Related Publication(s)

References

Link(s) to Reference(s)

Previously Published As

http://techreports.library.cornell.edu:8081/Dienst/UI/1.0/Display/cul.cs/TR94-1403

Government Document

ISBN

ISMN

ISSN

Other Identifiers

Rights

Rights URI

Types

technical report

Accessibility Feature

Accessibility Hazard

Accessibility Summary

Link(s) to Catalog Record