Page 249 - DCAP403_Operating System

Operating System

Notes 13.8.5 Semaphores
13.8.6 Shared Memory
13.9 Network Structure

13.9.1 An Overview of TCP/IP Networking
13.9.2 The Linux TCP/IP Networking Layers
13.9.3 The BSD Socket Interface
13.9.4 The INET Socket Layer
13.9.5 The IP Layer
13.9.6 The Address Resolution Protocol (ARP)
13.9.7 IP Routing
13.10 Security
13.11 Summary
13.12 Keywords
13.13 Review Questions
13.14 Further Readings

Objectives

After studying this unit, you will be able to:
Describe design principles and kernel modules
Know process management and process scheduling
Explain memory management and fi le systems
Know Input & Output

Introduction

The objective of this unit is to introduce to the Linux operating system. Linux (often pronounced
LIH-nuhks with a short “i”) is a Unix-like operating system that was designed to provide personal
computer users a free or very low-cost operating system comparable to traditional and usually

more expensive Unix systems. Linux has a reputation as a very efficient and fast-performing
system. Linux’s kernel (the central part of the operating system) was developed by Linus Torvalds
at the University of Helsinki in Finland. To complete the operating system, Torvalds and other
team members made use of system components developed by members of the Free Software
Foundation for the GNU Project.
Linux is a remarkably complete operating system, including a graphical user interface, an
X Window System, TCP/IP, the Emacs editor, and other components usually found in a
comprehensive Unix system. Although copyrights are held by various creators of Linux’s
components, Linux is distributed using the Free Software Foundation’s copyleft stipulations that

mean any modified version that is redistributed must in turn be freely available.
Unlike Windows and other proprietary systems, Linux is publicly open and extendible by
contributors. Because it conforms to the Portable Operating System Interface standard user and
programming interfaces, developers can write programs that can be ported to other operating
systems. Linux comes in versions for all the major microprocessor platforms including the Intel,
PowerPC, Sparc, and Alpha platforms. It’s also available on IBM’s S/390. Linux is distributed
commercially by a number of companies.

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