LinuxBasics

What is an Operating System (OS)?• An Operating System (OS)

is an interface between hardware and user which is responsible for the management and coordination of activities and the sharing of the resources of the computer that acts as a host for computing applications run on the machine.

What is an Operating System (OS)?• An Operating System is a

computer program that manages the resources of a computer. It accepts keyboard or mouse inputs from users and displays the results of the actions and allows the user to run applications, or communicate with other computers via networked connections.

Functions Of Operating SystemToday most operating systems perform the following important functions:

• 1. Processor management, that is, assignment of processor to different tasks being performed by the computer system.

• 2. Memory management, that is, allocation of main memory and other storage areas to the system programs as well as user programs and data.

• 3. Input/output management, that is, co-ordination and assignment of the different output and input device while one or more programs are being executed.

• 4. File management, that is, the storage of file of various storage devices to another. It also allows all files to be easily changed and modified through the use of text editors or some other files manipulation routines.

……

Common Operating Systems

The primary operating systems in use are Windows (Windows 98, XP, Vista, 7, 8), Macintosh OS X, the many versions of Linux and Unix. DOS is still used for some applications, and there are many other special-purpose operating systems (Embedded Linux).

Android is a mobile operating system (OS) based on the Linux kernel and currently developed by Google.

What is Linux?• The GNU operating system is a complete free software system, upward-

compatible with Unix. GNU stands for “GNU's Not Unix”. Richard Stallman made the Initial Announcement of the GNU Project in September 1983. A longer version called the GNU Manifesto was published in September 1985. It has been translated into several other languages.

• Linux is an operating system that was initially created as a hobby by a young student, Linus Torvalds, at the University of Helsinki in Finland. Linus had an interest in Minix, a small UNIX system, and decided to develop a system that exceeded the Minix standards. He began his work in 1991 when he released version 0.02 and worked steadily until 1994 when version 1.0 of the Linux Kernel was released. The kernel, at the heart of all Linux systems, is developed and released under the GNU General Public License and its source code is freely available to everyone. It is this kernel that forms the base around which a Linux operating system is developed. There are now literally hundreds of companies and organizations and an equal number of individuals that have released their own versions of operating systems based on the Linux kernel.

Richard Stallman, father of the GNU Project

Linus displays Linux running on a notebook pc

Linux Kernel

• The Kernel is the heart of the Linux operating system, responsible for controlling the computer’s resource and scheduling user jobs so that each one gets its fair share of the resources. Programs interact with the kernel through special functions with well-known names, called system calls.

The shell and other basicTime-sharing utilities

The LinuxSystem kernel

Computerhardware

Complier

SpreadsheetCalculators

InventoryControlSystem

Formatters

Editors

CalendarSystems

Mail andMessagefacilities

Interpreters

DatabaseManagement

systems

Wordprocessors

The Linux Operating System

Different Distributions of Linux

• Red Hat: http://fedoraproject.org

• CentOS : http://www.centos.org/

• Ubuntu: http://www.ubuntu.com

• Mandrake: http://www.linux-mandrake.org

• Debian: http://www.debian.org

• Knoppix: http://www.knoppix.net/

CentOS(http://www.centos.org)

Cent OS’s main advantage over RedHat enterprise is

the fact that it is free.

Download ISO image file from: http://mirror.centos.org/centos/5/isos/

orhttp://mirror.centos.org/centos/6/isos/

Burn: CDBurnerXP orNero Burning ROM

How to Get CentOS

See Installation Guide (http://www.centos.org/docs/5/html/5.2/Installation_Guide/)

CentOS 5 Installation Process(http://www.ee.cuhk.edu.hk/~htlau/CentOS5InstallationProcess.ppt)

Installation

After installation, remember to start the services (SSH, FTP, Web, etc.) you want to run by using System – Administration – Server Settings – Services

SSH and FTP: already started Web: httpd

Start Services

Menu

Software Collection (Firefox, OpenOffice, multimedia software, etc.)

Similar to Windows and quite easy to use

But Linux is mainly used to act as free (SSH, Web, FTP, Email, etc.) server

Environment

Up already after installation

Use terminal to try. Other computers can use SSH client or PuTTY to connect to SSH server

PuTTY can be downloaded from http://winscp.net/download/putty.exe

SSH client can be downloaded from https://www.cuhk.edu.hk/itsc/ssh/index2.html

SSH Server

Up already after installation

Other computers can use Secure File Transfer Client or WinSCP to connect and then upload or download files

WinSCP can be downloaded from http://winscp.net/download/winscp556.zip

FTP Server

You may use other computers (Frontpage, Dreamweaver, etc.) to create homepage and then use FTP or USB drive to copy the homepage files to /var/www/html/

Other computers use browsers to connect to http://hostname or http://IPAddress, e.g., http://137.189.35.222

Apache Web Server

The Linux Home Page at Linux Online (http://www.linux.org/)

鳥哥的 Linux 私房菜 (http://linux.vbird.org/)

Google (use it to search useful information)

Basic UNIX commands (http://mally.stanford.edu/~sr/computing/basic-unix.html)

Linux Documentation

The most useful documentation (http://www.centos.org/docs/5/html/5.2/Deployment_Guide/)

CentOS Documentation