Linux+ Unit 01

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Introduction to Linux Unit objectives  Outline the key features of the Linux operating system  List the advantages of using Linux  Describe the history of the Linux operating system  Explain the common uses of Linux in the industry today

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Topic A    

Topic A: Linux as an operating system Topic B: Advantages of Linux Topic C: History of Linux Topic D: Common uses of Linux

Components of a computer Course ILT

 Hardware – Physical components inside a computer

 Software – Instructions that understand how to use the hardware

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Role of the operating system  The operating system carries out tasks by interacting with users, applications, and computer hardware

Operating system components Course ILT

 Device driver – Software containing instructions to control computer hardware

 User interface – What the user sees and uses to interact with OS and application programs

Graphical user interface (GUI) Course ILT

The default Red Hat 9 GUI

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Exercise A-1

Discussing operating systems

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The Linux operating system  Runs many applications on a variety of different hardware  A multi-user and multitasking OS

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Versions of Linux OS  Core component: Linux kernel  Kernel version determines version of the OS  New versions add capabilities or fix bugs

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Identifying kernel versions  Major number  Minor number – If odd, developmental kernel – If even, production kernel

 Revision number

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Exercise A-2

Understanding Linux

Licensing Linux Course ILT

 Open Source Software (OSS) – The source code making up the program is freely available to anyone who wants to examine, utilize, change, or improve upon it

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Implications of OSS  Developed rapidly through widespread collaboration  Bugs are promptly noted and fixed  Features evolve very quickly based on users’ needs  Value of the software increases, because it is based on usefulness, not price

Types of open source licenses Course ILT

 GNU Public License (GPL) – Source code must be freely available

 Free Software Foundation (FSF) – Promotes and encourages collaboration between developers

 Artistic license – Allows free distribution, but changes happen only at discretion of original author

Types of closed source licenses

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 Freeware – Distributed free of charge – Source code is not available

 Shareware – Initially free but requires payment after a period of time or usage

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Exercise A-3

Discussing Linux licenses

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Topic B    

Topic A: Linux as an operating system Topic B: Advantages of Linux Topic C: History of Linux Topic D: Common uses of Linux

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Advantages of Linux       

Risk reduction Meeting business needs Stability and security Hardware portability Ease of customization Ease of obtaining support Cost reduction

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Risk factors  Software discontinued  Modifications no longer run on existing hardware  Upgrades force changes beyond the customer’s actual need  Maintenance provided through expensive service contracts by limited number of persons  Discontinuation of support  Failure and disappearance of the vendor

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Meeting business needs  Common software available for Linux includes: – Scientific and engineering software – Software emulators – Web servers, Web browsers, and e-commerce suites – Desktop productivity software – Graphics manipulation software – Database software – Security software

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Stability and security  Closed source operating-system customers must rely on the vendor to fix bugs  Waiting for a hot fix may take weeks or months  Bugs in OSS programs can be identified and fixed very quickly  Security loopholes are quickly identified and fixed

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Flexibility with hardware platforms  Partial list of hardware platforms on which Linux can run: – – – – – – – – – – –

Intel Itanium Mainframe (S/390) Cirrus Logic ARM DEC Alpha MIPS M68K PA-RISC SPARC Ultra-SPARC PowerPC (Macintosh)

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Ease of customization  The ability to control the inner workings of an operating system  Compile the kernel to include only the support needed for the job at hand  Install only the software needed for the task

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Ease of obtaining support  Frequently Asked Questions (FAQs)  HOWTO documents  Linux User Group (LUG) – An open forum of Linux users who discuss problems and learn from each other

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Cost reduction

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Exercise B-1

Discussing the advantages of Linux

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Topic C    

Topic A: Linux as an operating system Topic B: Advantages of Linux Topic C: History of Linux Topic D: Uses of Linux

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History of Linux

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Roots of Linux  Multiplexed Information and Computing Service (MULTICS) – Prototype time-sharing OS developed in the late 1960s

 UNIX – The first true multitasking, multi-user OS – The OS from which Linux originated

The hacker culture Course ILT

 Hacker – Someone with the intent of expanding their knowledge of computing through experimentation

 Cracker – Someone who illegally uses computers for personal benefit or to cause damage

 GNU Project – Free operating system project started by Richard Stallman

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Exercise C-1

Discussing Linux history

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Linux distributions  Use the commonly developed Linux kernel  Packaged with add-on software  Provide convenience and integration

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GNU Object Model Environment (GNOME)

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Kommon Desktop Environment (KDE)

Package managers and tarballs Course ILT

 Package manager – Software used to install, maintain, and remove other software programs by storing information in a central database

 Tarball – Compressed archive of files that contain scripts that install software

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Linux distributions

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Exercise C-2

Discussing Linux distributions

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Topic D    

Topic A: Linux as an operating system Topic B: Advantages of Linux Topic C: History of Linux Topic D: Common uses of Linux

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Common uses of Linux      

Internet servers File and print servers Application servers Supercomputers Scientific/engineering computations Desktop operating systems

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Internet servers       

Mail services Routing FTP services Firewalls and proxy services Web services News services DNS services

Mail services Course ILT

 Mail Transfer Agent (MTA) – An e-mail server

 Mail Delivery Agent (MDA) – Service that downloads e-mail from an MTA

 Mail User Agent (MUA) – Program that allows e-mail to be read and composed

Routing Course ILT

 Routing – Core service that is necessary for Internet to function – Linux provides support for routing and is easily customizable

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Firewalls  Firewalls protect companies from outside intruders  Linux has firewall support directly built into the kernel

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DNS services  Computers communicating on a network need to be uniquely identified – Each computer is assigned a number called an Internet Protocol (IP) address – IP addresses are matched to userfriendly names – Names are called Fully Qualified Domain Names (FQDNs)

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Exercise D-1

Linux as an Internet server

File servers Course ILT

 File servers provide: – – – –

Storage Security Sharing Portability

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Exercise D-2

Linux as a file and print server

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Application servers  Application server  Database Management Systems – Collection of programs and tools designed to allow for the creation, modification, manipulation, maintenance, and access of information from databases

Supercomputers Course ILT

 Scalability – Ability of computers to increase workload as the number of processors increases

 Clustering – Several smaller computers acting as one large supercomputer – Beowulf clustering

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Scientific/engineering workstations  There are many OSS programs available in many different scientific and engineering fields, including: – – – – – – –

Physics, astrophysics, and biophysics Fluid dynamics and geophysics Bio-computation Materials and polymer chemistry General mathematics and optimization Data mining Number theory

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Exercise D-3

Linux in business and science

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Desktop operating system      

Text editors Word processors Graphics editing software Desktop publishing software Financial software Office productivity suites

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Exercise D-4

Linux as an office workstation

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Unit summary  Outlined the key features of the Linux operating system  Listed the advantages of using Linux  Described the history of the Linux operating system  Explained the common uses of Linux in the industry today