ITEC1420_Chapter 10 Linux Introduction PDF

CompTIA Linux+ Guide to Linux Certification Fourth Edition Chapter 10 Introduction to Linux  Objectives Explain the purpose of an operating system Outline the key features of the Linux operating system Describe the origins of the...

CompTIA Linux+ Guide to Linux Certification Fourth Edition Chapter 10 Introduction to Linux  Objectives Explain the purpose of an operating system Outline the key features of the Linux operating system Describe the origins of the Linux operating system Identify the characteristics of various Linux distributions and where to find them Explain the common uses of Linux in industry today CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 2  Operating Systems Computers have two fundamental components: – Hardware: physical components inside a computer. – Software: set of instructions or programs that allow hardware components to manipulate data. CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 3  Operating Systems Hardware components include: – Processor (CPU) – Physical memory (RAM) – Hard disk drives – CD and DVD drives – Flash memory card readers (SD cards) – Sound cards – Video cards – Circuit boards CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 4  Operating Systems Two different types of programs are executed on a computer: – Applications (apps): programs designed for a specific use and with which a user interacts – Operating system (OS) software: software components used to control the hardware of the computer CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 5  Operating Systems Device driver: software containing instructions that the OS uses to control and interact with a specific device. User interface: an application program that accepts user input indicating what is to be done, forwards this input to the OS for completion, and gives results back to the user. – Can be a command line prompt or a graphical user interface (GUI). CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 6  Operating Systems Figure 1-1: The role of operating system software CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 7  Operating Systems Graphical user interface (GUI): component of an OS that the user can interact with using the keyboard or the mouse. System services: applications that handle system- related tasks – Printing – Scheduling programs – Gaining network access CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 8  Operating Systems Figure 1-2: A Linux graphical user interface CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 9  The Linux Operating System Linux - an OS used to run a variety of applications on a variety of different hardware components. Supports Multitasking – Has the ability to manage thousands of tasks at the same time. Multi-user – Allows multiple users to access the system simultaneously CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 10  Versions of the Linux Operating System Core component is called the Linux kernel. – Written almost entirely in the C programming language. Software can be used to modify appearance of Linux, but the kernel is common to all Linux. Important to understand Linux kernel version numbers to decide which version is appropriate for user needs. CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 11  Identifying Kernel Versions Linux kernel versions are composed of: – Major number - indicates the major revision to the Linux kernel – Minor number - indicates the minor revision and stability of the Linux kernel If odd, referred to as a developmental kernel: a kernel which is not fully tested and with implied instability If even, referred to as a production kernel: a kernel that has been thoroughly tested and is declared to be stable – Revision number CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 12  Table 1-1: Latest revisions of common Linux kernels CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 13  Licensing Linux Open Source Software (OSS): programs distributed and licensed so that the source code is freely available to anyone who wants to examine, utilize, or improve upon it. Source code: refers to the list of instructions that a software developer writes to make up a program. Format and structure of source code follows rules defined by the programming language in which it was written CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 14  Licensing Linux Implications of OSS: – Software is developed very rapidly through widespread collaboration. – Software bugs (errors) are noted and promptly fixed – Software features evolve quickly based on users’ needs – The perceived value of the software increases because it is based on usefulness, not on price CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 15  Licensing Linux Table 1-2: Software types CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 16  Types of Open Source Licenses GNU Public License (GPL): – Developed by the Free Software Foundation (FSF) – Stipulates that the source code of any software published under its license must be freely available. – Users who modify the source code must also redistribute the modified code freely. Artistic license: OSS license allowing source code to be distributed freely, changed only at discretion of original author – Original author has the right to reject changes CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 17  Types of Closed Source Licenses Most closed source software is sold commercially – Usually bears label of manufacturer, such as Microsoft, Apple, or Electronic Arts. Freeware: distributed free of charge; source code is not available. Shareware: initially free, but requires payment after a period of time or for use of certain features. CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 18 Linux Advantages: Risk Reduction Changes in the market or customer needs may cause companies to change software frequently – Can be costly and time-consuming Support for closed source software may end. – Vendor may go out of business – Software version may be retired OSS products offer the opportunity to maintain and change the source code. CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 19 Linux Advantages: 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 CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 20  Linux Advantages: Stability and Security Customers using a closed source OS must rely on the OS vendor to fix any bugs. – Waiting for a hot fix may take weeks or months The collaborative open source approach to testing and fixing bugs increases the stability of Linux. Bugs and security loopholes in OSS programs can be identified and fixed quickly. – Code is freely available and scrutinized by many developers CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 21  Linux Advantages: Ease of Customization Ability to control the inner workings of the OS – To use Linux as an Internet Web server, recompile the kernel to include only the support needed to be an Internet Web server. Results in a much smaller and faster kernel – Can choose to install only software packages needed to perform required tasks – Linux supports several programming languages, such as shell and PERL scripts to customize or automate tasks CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 22  Linux Advantages: Cost Reduction Linux is less expensive than other Oss. – There is no cost associated with acquiring the software – A wealth of OSS can run on a variety of different hardware platforms running Linux The largest costs associated with Linux: – Costs associated with hiring people to maintain the Linux system Total cost of ownership (TCO): overall cost of using a particular OS CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 23  UNIX Evolved from Multiplexed Information and Computing Service (MULTICS). The first true multitasking, multiuser OS. UNIX was rewritten in the C programming language – Portable OS: able to run on different hardware platforms. AT&T sold UNIX source code to several companies – Each developed its own variety (or flavor) of UNIX yet adhered to standards agreed upon by all CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 24  UNIX Berkeley Software Distribution (BSD) – Version of the original UNIX source code Common flavors of UNIX today include: – Oracle’s Solaris (formerly SUN Microsystem’s) – Hewlett-Packard’s HP-UX – IBM’s AIX UNIX – Apple’s Macintosh OS X and iOS CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 25  Linux First developed by Linus Torvalds in 1991. – Published under the GNU license. Distribution: a collection of software containing the Linux kernel and libraries, combined with add-on software specific to a certain use. – Red Hat and SuSE CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 26  Linux Linux is simply a by-product of OSS development. Since 2000, there has been interest in embedded Linux – Linux OSs that run on smaller hardware devices such as mobile devices). Because Linux is currently very well developed – More application development can be expected from the OSS community in the next decade CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 27  Linux Distributions Table 1-4: Common Linux distributions CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 28  Linux Distributions Table 1-4 (cont’d): Common Linux distributions CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 29  Common Uses of Linux Linux may be customized to provide services for a variety of companies in a variety of situations. Workstation services: services used on a local computer Server services: services made available for other computers across a network CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 30  Common Uses of Linux Linux configurations commonly used today: – Internet servers – File and print servers – Application servers – Cloud systems – Supercomputers – Scientific workstations – Office/personal workstations – Mobile devices CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 31  Summary Linux is an OS whose kernel and additional software are freely developed and improved upon by a large community of software developers. Published under the GNU Public License – Referred to as Open Source Software (OSS) Companies find Linux a stable, low-risk, and flexible alternative to other OSs CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 32  Summary Available in different distributions, all having a common kernel, but packaged with different OSS applications. CompTIA Linux+ Guide to Linux Certification, 4th Edition © Cengage Learning 2016 33