Need of OS for Embedded System

Updated on 2017/06/21 13:09

Syllabus

  • Need of Operating System (OS) in developing complex applications in embedded system
  • Desired features of operating system & hardware support from processor

Introduction

In earlier day’s, users had to design the application according to the internal structure of the hardware. Later, the OS enabled the users to do so without such concerns.
In general the boundary between the hardware & software is transparent to the user.

Usage of Operating System

  1. Easy interaction between the human & Embedded system
  2. Loading & scheduling users program
  3. Controlling input & output
  4. Controlling program execution
  5. Managing use of main memory
  6. Providing security to users program

Need of Operating System

Process Management

Process management module of OS takes care of:

  • creation & deletion of processes
  • scheduling of system resources to different proceses
  • providing mechanism for synchronization & communication among processes

Memory Management

The memory management module of OS takes care of:

  • allocation & reallocation of memory space to the various program in need of this resource

File Management

File management functions of an OS help in:

  • keeping track of all different files
  • maintaining the integrity of data stored in the files including file directory structure

Security

The security modules of OS: 

  • protects the resources & information of a computer system against destruction & unauthorized access

Network Management & Communication

  • Managing all network communication activities

User interface

  • Provides the interface between user and system

Command Interpretation

The Command Interpretation module of OS:

  • interprets user commands
  • directs the system resources to handle the requests

With this mode of interaction with the system, the user is usually not too concerned with the hardware details of the system.

Input/Output or Device Management

  • coordination & control of various input & output devices
  • receiving the request for I/O interrupts & communicating back to the requesting process

Job Control

  • To run an application program, user must communicate with the OS telling it what to do. He does this using Operating System job control language or JCL.
  • JCL consists of a number of commands, called system commands that control the functioning of the OS.

Desired Features of OS & Hardware Support from Processor

Clock and Timer support

Important for:

  • Real time application
  • High res­olutions
  • vital part of every real time OS

Static priority levels

Real time Priority levels Must support static priority levels. Tra­ditional OS dynamically changes the priority levels for maximizing system throughput.

Fast Task Preemption

Higher priority task waits before it is al­lowed to execute.

Predictable and Fast Interrupt

  • Latency Time delay between the occurrence of interrupt and running of the corre­sponding ISR should be less. 
  • Nested interrupts.

Resource sharing

  • Real time task. 
  • Avoiding missing deadlines. (In Traditional resource sharing techniques, response time of tasks can become unbounded leading to deadline miss­ing.)

Support for Asynchronous I/O

In synchronous I/O, execution of the process is blocked while it waits for the results of the system call.

Memory

  • Support of Memory Management/ protection

References

Tags:
Created by Admin on 2017/04/10 11:28