2023 1 embedded systems chapter 4

Content ▪ Introduce to embedded OS ▪ Basics of embedded Linux ▪ Linux boot process▪ Manage Linux system▪ Git source code management... Embedded OSGoals of Operating System▪ Resource Mana

HỆ THỐNG NHÚNG

Dr Thanh Nguyen

Email: thanh.nguyenngoc@phenikaa-uni.edu.vnOffice: Room 606 - Building A4

Chapter 4: Embedded Operating System

Content

▪ Introduce to embedded OS ▪ Basics of embedded Linux ▪ Linux boot process

▪ Manage Linux system

▪ Git source code management

Embedded OS

Goals of Operating System

▪ Resource Management: Disk, CPU cycles, etc must be managed efficiently to maximize

overall system performance

▪ Resource Abstraction: Software interface to simplify use of hardware resources

▪ Virtualization: Supports resource sharing –gives each process the appearance of an unshared resource

Embedded OS

Components of an OS

Embedded OS

Structures of OS

• Simple structure:

• Do not have well defined structure and are small, simple and limited systems • MS-DOS is an example

• Entire system to crash if one of the user programs fails

https://www.geeksforgeeks.org/different-approaches-or-structures-of-operating-systems/

Embedded OS

Structures of OS

• Layers structure:

• Layers are so designed that each layer uses the functions of the lower level

Embedded OS

Structures of OS

• Modular structure:

• The best structure for an OS

• Involve designing of a modular kernel • Set of core components

• Other services are added as dynamically loadable modules

https://www.geeksforgeeks.org/different-approaches-or-structures-of-operating-systems/

Embedded OS

Abstract View of System

Embedded OS

Applications

Embedded OS

Real time system

“A real time system is one in which the correctness of the computations

not only depends upon the logical correctness of the computation but also upon the time at which the result is produced If the timing constraints of the system are not met, system failure is said to have occurred.”

-Donald

Gillies-Embedded OS

Real time OS

• Hard Real Time System

• Failure to meet deadlines is fatal • example: Flight Control System

• Soft Real Time System

• Late completion of jobs is undesirable but not fatal.

• System performance degrades as more & more jobs miss deadlines • Online Databases

Embedded OS

Real time OS

• Hard Real Time System

• Validation by provably correct procedures or extensive simulation that the system always meets the timings constraints

• Soft Real Time System

• Demonstration of jobs meeting some statistical constraints suffices.

Embedded OS

Role of an OS in Real Time Systems

• Standalone Applications

• Often no OS involved

• Micro controller based Embedded Systems • Some Real Time Applications are huge & complex

• Multiple threads

• Complicated Synchronization Requirements • Filesystem / Network / Windowing support

• OS primitives reduce the software design time

Embedded Linux

• embedded system: System of computing hardware with integrated software that was designed to be used for a specific application

• Linux: free and open-source, monolithic, modular, multitasking, Unix-like operating system kernel.

Embedded Linux

Linux history

Linus Torvalds

Embedded Linux

Linux vs Window

Embedded Linux

Linux vs Window

Wide variety of computer hardware

(mobile phone, tablet, video console, super computers,…)

On PC’s desktops, laptops, servers, phones

File system support: Ext2, Ext3, Ext4File system support: FAT, FAT32, NTFS

Text command: BASH Text command: DOS – like commandsUser interface: GNOME or KDEWindows Aero

Embedded Linux

Linux kernel

• Kernel is the core of Linux operating systems • Official website: https://kernel.org

• OS based on Linux kernel – Linux Distributions: Ubuntu, Fedora, Debian • Almost 600 Linux Distributions exist.

Embedded Linux

Linux kernel

https://en.wikipedia.org/wiki/Linux_kernel

Embedded Linux

Commands in Linux terminal• pwd: print working directory• mkdir: make directory

• rmdir: remove directory

Embedded Linux

1 sudo apt-get install git-core : install git

2 git clone https://github.com/WiringPi/WiringPi.git : clone WiringPi folder from git server

3 cd WiringPi: Change directory to home/”user”/WiringPi/

4 ./build :cài đặt theo các bước trên bộ thư viện wiringPi sẽ được

cài đặt trên máy

5 gpio -v : kiểm tra xem quá trình cái đặt có thành công hay không6 gpio readall : cấu hình các chân hiện tại của kit Raspberry Pi

Embedded Linux

Summary

▪ Introduce to embedded OS▪ Basics of embedded Linux▪ Linux boot process

▪ Manage Linux system

▪ Git source code management