Download Linux Operations and Administration

About the Presentations
• The presentations cover the objectives found in the
opening of each chapter.
• All chapter objectives are listed in the beginning of
each presentation.
• You may customize the presentations to fit your
class needs.
• Some figures from the chapters are included. A
complete set of images from the book can be found
on the Instructor Resources disc.
Linux Operations and
Administration
Chapter One
Introduction to the Linux Operating
System
Objectives
• Summarize the functions of an operating system
• Identify key historical points in the development of
Linux
• Explain the components of the Linux architecture
and features of the operating system
Linux Operations and Administration
3
Overview of Operating System
Functions
• Linux
– Practical alternative to more costly Windows and
Macintosh operating systems
– Includes:
•
•
•
•
•
Graphical desktop
Web browser
E-mail
Sound and video
Any other feature that Windows has to offer
Linux Operations and Administration
4
Software Licensing Agreements
• User does not actually own the software
– Only granted a license to use it
• Table 1-1
– Licensing terms
• Open source
– Software distributed with its source code
– Users can view or modify it
• All Linux versions are open source
• Source code
– Instructions defining how a program works
Linux Operations and Administration
5
Software Licensing Agreements
(cont’d.)
Table 1-1 Licensing agreement terms
Linux Operations and Administration
6
Software Licensing Agreements
(cont’d.)
• Linux kernel licensed under General Public License
(GPL)
• Activity 1-1: Reviewing Licensing Agreements
– Examine the licensing agreement of an application
of your choice and compare it with the GPL
Linux Operations and Administration
7
Functions of an Operating System
• Operating system
– Software that’s designed to control hardware
– Provides an interface between computer hardware
and software
• Kernel
– Performs the most basic computing functions
• Table 1-2
– Summarizes common OSs
Linux Operations and Administration
8
Functions of an Operating System
(cont’d.)
Table 1-2 Features of common operating systems
Linux Operations and Administration
9
Functions of an Operating System
(cont’d.)
• Most OSs include:
– User interface
• Graphical user interface (GUI)
– Enables users to interact with computers by using
graphical elements, such as menus and buttons
• Command-line interface (CLI)
– Users communicate with the computer by typing
commands
Linux Operations and Administration
10
Functions of an Operating System
(cont’d.)
– File systems
• Find and access files
– Device drivers
• Control hardware devices
– System services
• Run in the background and carry out applicationrelated tasks
Linux Operations and Administration
11
History of Linux
• American Telephone & Telegraph (AT&T)
– By 1969, 90% of American homes had AT&T phone
service
– Testing and research conducted at Bell Laboratories
• UNIX operating system
– Created at Bell Labs by Dennis Ritchie and Ken
Thompson
– Many professors began using it for testing and
research in university labs
Linux Operations and Administration
12
History of Linux (cont’d.)
• In early 1980s, AT&T decided to license UNIX and
charge institutions a hefty price to use it
• Richard Stallman
– Created the GNU Project
– Developed the GPL
– Believes software should be free
Linux Operations and Administration
13
History of Linux (cont’d.)
• GPL
– You can use, view, and change the source code
– You are able to redistribute the software and sell it
for a profit
– If you decide to sell the software, you must make the
source code available
• MINIX
– Created by Andrew Tanenbaum to teach students
how to use an OS
– Source code made available to everybody
Linux Operations and Administration
14
History of Linux (cont’d.)
• Linus Torvalds
– Created his own kernel in 1991
– Called the Linux kernel
– Licensed through the GPL
• Many different versions (distributions)
–
–
–
–
–
–
Red Hat (www.redhat.com)
Ubuntu (www.ubuntu.com)
Debian (www.debian.org)
PCLinuxOS (http://pclinuxos.com)
FreeBSD (www.freebsd.org)
openSUSE (www.novell.com/linux)
Linux Operations and Administration
15
History of Linux (cont’d.)
Table 1-3 Linux timeline
Linux Operations and Administration
16
Overview of SUSE
• Developed in Germany in 1992
– By Hubert Mantel, Burchard Steinbild, Roland Dyroff,
and Thomas Fehr
• Acronym for “Software und System Entwicklung”
– Software and System Development
• Top Linux seller in Europe
• Sold to Novell for $210 million
Linux Operations and Administration
17
Overview of SUSE (cont’d.)
• OpenSUSE
– Comes with the Linux kernel and the latest versions
of two desktop environments KDE and GNOME
• Yet another Setup Tool (YaST)
– Configuration tool that enables administrators to
install and manage software
Linux Operations and Administration
18
Linux Architecture
• Modular system
– All components are separate from one another
– Makes it possible for different teams to develop
components that don’t affect one another
• Linux distribution
– Consists of all the Linux components put together
and released as one OS
Linux Operations and Administration
19
Figure 1-1 Components
of the Linux architecture
©Cengage Learning 2013
Linux Operations and Administration
20
Linux Architecture (cont’d.)
• Kernel
– Core of the OS
– Manages hardware, such as disk drives and memory
• Shell
– Interface that accepts and translates user input so
that the kernel can process it
• Daemons
– Programs that run in the background independently
of the user
– Called services in Windows
Linux Operations and Administration
21
Linux Architecture (cont’d.)
• Applications
– Programs that require an OS to run
– Give users a specific function, such as wordprocessing programs, media players, etc.
Linux Operations and Administration
22
Kernel
• Linux kernel
– Licensed under the GPL
– Allows public access to the source code
• Resource manager
– Manages processes and memory
– Can perform multiple processes at the same time
• Process
– Program the kernel launches into memory for the
purpose of performing specific tasks
Linux Operations and Administration
23
Kernel (cont’d.)
• Random access memory (RAM)
– Storage space where a computer reads and writes
data
– Considered “volatile” storage
• Data stored there is erased when the computer shuts
down
• Demand paging
– Load only needed sections of a program into RAM
Linux Operations and Administration
24
Linux Desktop Environments
• Desktop environments available in openSUSE
–
–
–
–
K Desktop Environment (KDE)
GNU Network Object Model Environment (GNOME)
Very similar
Differ mainly in the programming language used to
write them
Linux Operations and Administration
25
Figure 1-2 The KDE interface in openSUSE
©Cengage Learning 2013
Linux Operations and Administration
26
Figure 1-3 The GNOME interface in openSUSE
©Cengage Learning 2013
Linux Operations and Administration
27
Linux File Structure
• Organized in a hierarchical, treelike structure
• Top level
– Root directory
– Indicated with the / symbol
• Everything in Linux is considered a file
– Device files
– “Regular” files
– Directory files
Linux Operations and Administration
28
Linux File Structure (cont’d.)
• Device file
– Special file stored in the /dev directory
– Represents a hardware device on the system
• Regular files
– Files containing data
• Directory file
– Like a folder in Windows
– Can contain files and other directories
Linux Operations and Administration
29
Features of Linux
• Multiuser
– Enables multiple users to log on to a single
computer at the same time
• Multitasking
– Multiple processes can run simultaneously
• Preemptive multitasking
– Scheduler decides when a process stops and
another process starts
Linux Operations and Administration
30
Features of Linux (cont’d.)
• Networking connectivity
– Uses Transmission Control Protocol/Internet
Protocol (TCP/IP)
• Internationally accepted set of rules for connecting
computers to the Internet and most other networks
• Security
– Login and password authentication
– File ownership and permissions
– Firewall for protecting network resources from users
outside the network
Linux Operations and Administration
31
Command Shells Available in Linux
• Shell
– Command-line interface between users and the
kernel
• Used by administrators for more advanced
configuration tasks
• Table 1-4
– Summarizes common Linux shells
– Stored in the /bin directory
Linux Operations and Administration
32
Command Shells Available in Linux
(cont’d.)
Table 1-4 Common shells in Linux
Linux Operations and Administration
33
Summary
• All Linux distributions
– Open source and licensed under the General Public
License (GPL)
• Linux distributions
– Include graphical desktop environment, a Web
browser, e-mail, sound, video, and networking
capability
– Comparable with rival operating systems
• Kernel
– Performs the most basic computing functions
Linux Operations and Administration
34
Summary (cont’d.)
• Main user interfaces
– Graphical user interface (GUI)
– Command-line interface
• GNU Project
– Protest against licensing UNIX as a for-profit
software product
• Linux architecture
– Kernel, shell, applications, GUI, and desktop
environment
Linux Operations and Administration
35