scholarly journals Research on Real-Time System and Related Graph Task Model

2021 ◽  
Vol 2066 (1) ◽  
pp. 012054
Author(s):  
Juan Xiao ◽  
Song Wang ◽  
Sheng Duan ◽  
Shanglin Li
Keyword(s):  
Operating System ◽  
Real Time ◽  
Directed Graph ◽  
Scheduling Algorithm ◽  
Time Constraint ◽  
Time System ◽  
Real Time System ◽  
Real Time Operating System ◽  
Task Model ◽  
Time Accuracy

Abstract Generally speaking, real-time system is considered to be able to influence the environment by receiving and processing data, and returning calculation results rapid enough, so as to control the environment. In computer science, real-time system describes the software and hardware system affected by time constraints, and its correctness relies on the logical correctness of the function and the time when the result is generated. According to the main characteristics of real-time operating system, such as time constraint, predictability and reliability, it puts forward higher requirements for the time accuracy and reliability of real-time operating system. This paper first introduces the real-time system from its main characteristics, related concepts and scheduling algorithm. Then five classical graph based task models of real-time system are introduced. Finally, this paper introduces the directed graph realtime task model from two aspects of definition and semantics. As an extension of realtime system task model, directed graph real-time task model is considered to be able to provide real-time systems with stronger expressive power and support the formal study of time constraint problems.

A Study on the Design Method of the Real-Time System Software Based on RTOS

2014 ◽  
Vol 513-517 ◽  
pp. 2487-2491
Author(s):  
Dong Zhao ◽  
Shang Wei Jiang ◽  
Hong Wei Zhao ◽  
Xin Tong Yu
Keyword(s):  
Operating System ◽  
Real Time ◽  
Design Method ◽  
Control Flow ◽  
Functional Requirements ◽  
Time System ◽  
Real Time System ◽  
Real Time Operating System ◽  
The Real ◽  
Structured Analysis

This paper combines the characteristics of real-time embedded systems and the real-time operating system to propose a software engineering method and process which bases on the function structured analysis and task structured design. First in the process of structured analysis based on the Hatley-Pirbhai method, extracting and sorting out the data flow and control flow according to the functional requirements of the system, analyzing and processing the functions of the system, the dependency among the functions and the timing sequence, and then realizing the design of the specific functions of the system, next achieving the structural design through the improving method, it also simplifies the system design processes. At this time, just need to analyze and divide the processing which is obtained from the structural analysis to get the specific task, design the interfaces among the tasks and also every task to get the new design method of the embedded real-time operating system, which also solves hard issue of the traditional method which is the weak extracting and developing iteration in the embedded real-time system.

scholarly journals An Introduction to RTOS

2012 ◽  
pp. 285-289
Author(s):  
Sanjay Singh ◽  
Nishant Tripathi ◽  
Anil Kumar Chaudhary ◽  
Mahesh Kumar Singh
Keyword(s):  
Operating System ◽  
Real Time ◽  
Level Of Service ◽  
Real Time Systems ◽  
Time System ◽  
Real Time System ◽  
Real Time Operating System ◽  
System A ◽  
External Stimuli ◽  
Time Systems

RTOS (real time operating system) can be defined as “The ability of the operating system to provide a required level of service in bounded response time.” A real time system responds in a (timely) predictable way to unpredictable external stimuli arrivals. To build a predictable system, all its components (hardware & software) should enable this requirement to be fulfilled. Traffic on a bus for example should take place in a way allowing all events to be managed within the prescribe time limit. However it should not be forgotten that a good RTOS is only is building block. Using it in a wrongly designed system may lead to a malfunctioning of the RT system. A good RTOS can be defined as one that has a bounded (predictable) behavior under all system load scenarios (simultaneous interrupts and thread execution). In RT system, each individual deadline should be met. Real-time systems are designed to control and monitor their environment. Most of these systems are using sensors to collect environment state and use actuators to change something.

Software Design of Aircraft Electrical Load Management Center Based on μC/OS-II

2011 ◽  
Vol 268-270 ◽  
pp. 552-556
Author(s):  
Jian Jun Wu ◽  
Wei Wan ◽  
Da Hai Zhao
Keyword(s):  
Operating System ◽  
Real Time ◽  
Software Design ◽  
Load Management ◽  
Electrical Load ◽  
Time System ◽  
Real Time System ◽  
Single Task ◽  
Real Time Operating System ◽  
Priority Allocation

This paper introduces that embedded real time operating system μC/OS-II is applied in software design of aircraft electrical load management center. Firstly, the μC/OS-II and its running on ARM are briefly presented. Then the method of two system running modes is given in details. And the tasks assignment, priority allocation and communication between tasks under both two modes are also provided. Results show that multitask schedule managements of real-time system has solved the problem of poor real-time in a single task system. And the reliability of the system has been greatly improved.

An Overview of the SUSI Control System

1994 ◽  
Vol 158 ◽  
pp. 181-183
Author(s):  
R. A. Minard ◽  
A. J. Booth ◽  
W. J. Tango ◽  
T. Ten Brummelaar ◽  
H. Bennis ◽  
...  
Keyword(s):  
Operating System ◽  
Control System ◽  
Real Time ◽  
Network Protocols ◽  
Time System ◽  
Real Time System ◽  
Real Time Operating System ◽  
Multiple Processors ◽  
Synchronous Operation

The SUSI control system is a distributed real-time system currently consisting of 17 processors. A custom real-time operating system and network protocols ensure synchronous operation of servo loops across multiple processors.

scholarly journals A Hybrid Multiprocessor Scheduler for Soft Real-Time System with Processor Affinity Concept

2021 ◽  
Vol 2089 (1) ◽  
pp. 012022
Author(s):  
Ms Jayna Donga ◽  
M.S. Holia
Keyword(s):  
Operating System ◽  
Real Time ◽  
Migration Policy ◽  
Time System ◽  
Real Time System ◽  
Real Time Operating System ◽  
Flexible Approach ◽  
Time Extension ◽  
Overall Performance ◽  
Traditional Approaches

Abstract Now a days numerous real-time OS like QNX, VxWorks, LynxOS and real-time extension of Linux practicing the processor affinity concept to schedule the real-time tasks and it offers more flexible approach instead of traditional approaches defined in the literature. Limiting the migration may reduce the context switch overhead and improve the cache performance but it largely influence on other parameters which are most important for the any real-time operating system. It degrades overall performance by decreasing the schedulability of tasks, increase the deadline miss ratio. This paper presents the problem in existing processor affinity based approach which confines the schedulability of the tasks and designed a novel processor affinity based algorithm to enhance the schedulability of the tasks and decreases the average deadline miss ratio by providing the flexible migration policy with the priority reassignment mechanism.

scholarly journals Limited Non-Preemptive EDF Scheduling for a Real-Time System with Symmetry Multiprocessors

Symmetry ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 172 ◽  
Author(s):  
Hoyoun Lee ◽  
Jinkyu Lee
Keyword(s):  
Real Time ◽  
Scheduling Algorithm ◽  
Schedulability Analysis ◽  
Timing Constraints ◽  
Limited Information ◽  
Time System ◽  
Real Time System ◽  
System A ◽  
The Future ◽  
Earliest Deadline

In a real-time system, a series of jobs invoked by each task should finish its execution before its deadline, and EDF (Earliest Deadline First) is one of the most popular scheduling algorithms to meet such timing constraints of a set of given tasks. However, EDF is known to be ineffective in meeting timing constraints for non-preemptive tasks (which disallow any preemption) when the system does not know the future job release patterns of the tasks. In this paper, we develop a scheduling algorithm for a real-time system with a symmetry multiprocessor platform, which requires only limited information about the future job release patterns of a set of non-preemptive tasks, called LCEDF. We then derive its schedulability analysis that provides timing guarantees of the non-preemptive task set on a symmetry multiprocessor platform. Via simulations, we demonstrate the proposed schedulability analysis for LCEDF significantly improves the schedulability performance in meeting timing constraints of a set of non-preemptive tasks up to 20.16%, compared to vanilla non-preemptive EDF.

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