Linux Operations and Administration Chapter One Introduction to

Linux Operations and Administration Chapter One Introduction to the Linux Operating System

Before we begin • Linux – What it be? – Learn why? Linux Operations and Administration 2

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 • All Linux versions are open source – What is open source? – What is source code? Linux Operations and Administration 5

Software Licensing Agreements (cont’d. ) • 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 6

Functions of an Operating System • Operating system – Software that’s designed to control hardware – Provides an interface between computer hardware and software • Kernel Linux Operations and Administration 7

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 • Lets’ Draw!! Linux Operations and Administration 8

Functions of an Operating System (cont’d. ) – File systems • Find access files – Device drivers • Control hardware devices – System services • Run in the background and carry out applicationrelated tasks Linux Operations and Administration 9

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 10

History of Linux (cont’d. ) • In early 1980 s, 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 11

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 12

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) PCLinux. OS (http: //pclinuxos. com) Free. BSD (www. freebsd. org) open. SUSE (www. novell. com/linux) Linux Operations and Administration 13

History of Linux (cont’d. ) • Linus Torvalds • Many different versions (distributions) Linux Operations and Administration 14

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 15

Overview of SUSE (cont’d. ) • Open. SUSE – Comes with the Linux kernel and the latest versions of two desktop environments KDE and GNOME • Yet another Setup Tool (Ya. ST) – Configuration tool that enables administrators to install and manage software Linux Operations and Administration 16

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 17

Figure 1 -1 Components of the Linux architecture ©Cengage Learning 2013 Linux Operations and Administration 18

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 19

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 20

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 21

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 22

Linux Desktop Environments • Desktop environments available in open. SUSE – – 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 23

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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 25

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 26

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 27

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 28

Command Shells Available in Linux • Shell – Command-line interface between users and the kernel • Used by administrators for more advanced configuration tasks Linux Operations and Administration 29

Command Shells Available in Linux (cont’d. ) Table 1 -4 Common shells in Linux Operations and Administration 30

What terms should you know? Linux Operations and Administration 31