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Linux Guide to Linux Certification

Linux+ Guide to Linux Certification, 2e. 2. Operating Systems. Computers have two ... to control and interact with a specific type of computer hardware ...

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Linux Guide to Linux Certification

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  1. Linux+ Guide to Linux Certification, Second Edition Chapter 1 Introduction to Linux

  2. Operating Systems • Computers have two fundamental components: • Hardware: Physical components inside a computer • Software: Set of instructions or programs that understand how to use the hardware of the computer in a meaningful way Linux+ Guide to Linux Certification, 2e

  3. Operating Systems (continued) • Hardware components include: • Processor (CPU) • Physical memory (RAM) • Hard disk, floppy disk, and CD-ROM drives • Sound and video cards • Circuit boards Linux+ Guide to Linux Certification, 2e

  4. Operating Systems (continued) • Two different types of programs are executed on a computer: • Applications • Operating system (OS) software • Device Driver: Software containing instructions that the OS uses to control and interact with a specific type of computer hardware • User Interface: An application program that allows the user to interact with the OS and other application programs Linux+ Guide to Linux Certification, 2e

  5. Operating Systems (continued) Figure 1-1: The role of operating system software Linux+ Guide to Linux Certification, 2e

  6. Operating Systems (continued) • Graphical user interface (GUI): Component of an OS that provides a user-friendly interface • System services: Applications that handle system-related tasks • Printing • Scheduling programs • Network access Linux+ Guide to Linux Certification, 2e

  7. Operating Systems (continued) Figure 1-2: A Linux graphical user interface Linux+ Guide to Linux Certification, 2e

  8. The Linux Operating System • OS used to run a variety of applications on a variety of different hardware • Has the ability to manage thousands of tasks at the same time • Allows multiple users to access the system simultaneously • Multiuser and multitasking OS Linux+ Guide to Linux Certification, 2e

  9. 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 Linux+ Guide to Linux Certification, 2e

  10. Identifying Kernel Versions • Linux kernel versions are composed of: • Major number • Minor number • If odd, referred to as a developmental kernel • If even, referred to as a production kernel • Revision number Linux+ Guide to Linux Certification, 2e

  11. Identifying Kernel Versions (continued) Table 1-1: Latest revisions of common Linux kernels Linux+ Guide to Linux Certification, 2e

  12. Licensing Linux • Open Source Software (OSS): Programs distributed and licensed so that the source code is available to anyone who wants to examine, utilize, or improve upon it • Format and structure of source code follows rules defined by the programming language in which it was written Linux+ Guide to Linux Certification, 2e

  13. Licensing Linux (continued) • Implications of OSS: • Developed very rapidly through widespread collaboration • Bugs (errors) are noted and promptly fixed • Features evolve quickly based on users’ needs • Perceived value of the software increases because it is based on usefulness, not on price Linux+ Guide to Linux Certification, 2e

  14. Licensing Linux (continued) Table 1-2: Software types Linux+ Guide to Linux Certification, 2e

  15. Types of Closed Source Licenses • Most closed source software is sold commercially • e.g., Microsoft or Electronic Arts software • Freeware: Distributed free of charge; source code is not available • Shareware: Initially free, but requires payment after a period of time or usage Linux+ Guide to Linux Certification, 2e

  16. 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 Linux+ Guide to Linux Certification, 2e

  17. Linux Advantages:Ease of Customization • Ability to control the inner workings of an OS • To use Linux as an Internet Web server, compile the kernel to include only the support needed to be an Internet Web server • Results in a much smaller and faster kernel Linux+ Guide to Linux Certification, 2e

  18. Linux Advantages: Ease of Obtaining Support • Linux documentation can be found on the Internet • Frequently Asked Questions (FAQs) • HOWTO documents • Linux Newsgroups • Linux User Group (LUG): Open forum of Linux users who discuss and assist each other in using and modifying the Linux OS Linux+ Guide to Linux Certification, 2e

  19. Linux Advantages: Cost Reduction Table 1-3:Calculating the total cost of ownership Linux+ Guide to Linux Certification, 2e

  20. The History of Linux Figure 1-4: Timeline of UNIX and Linux development Linux+ Guide to Linux Certification, 2e

  21. UNIX • Evolved from Multiplexed Information and Computing Service (MULTICS) • The first true multitasking, multiuser OS • Written in the C programming language • Portable OS • OS from which Linux originated Linux+ Guide to Linux Certification, 2e

  22. UNIX (continued) • Berkeley Software Distribution (BSD) • Version of the original UNIX source code • Common flavors of UNIX today include: • Sun Microsystems’s Solaris • Hewlett-Packard’s HP-UX • IBM’s AIX UNIX Linux+ Guide to Linux Certification, 2e

  23. Linux • First developed by Linus Torvalds in 1991 • Published under the GNU license • Linux kernel developed collaboratively and centrally managed • Linux is simply a by-product of OSS development Linux+ Guide to Linux Certification, 2e

  24. Linux Distributions • Red Hat and SuSE • Distributions may appear different on the surface, but run the same kernel • Most distributions ship with a GUI that can be further customized to suit needs of the user • Core component of this GUI is X Windows Linux+ Guide to Linux Certification, 2e

  25. Linux Distributions (continued) • GUI environment: X Windows in combination with a window manager and desktop environment • Two competing GUI environments in Linux: • GNU Object Model Environment (GNOME) • Kommon Desktop Environment (KDE) Linux+ Guide to Linux Certification, 2e

  26. Linux Distributions (continued) Figure 1-5: The GNOME Desktop Linux+ Guide to Linux Certification, 2e

  27. Common Uses of 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 Linux+ Guide to Linux Certification, 2e

  28. Internet Servers: Mail Services • 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 by a user Linux+ Guide to Linux Certification, 2e

  29. Internet Servers:Routing and FTP Services • Routing: Provides interconnection between separate networks • Core service necessary for Internet to function • Linux provides support for routing and is easily customizable • File Transfer Protocol (FTP) Services: Most common and efficient method for transferring files over the Internet Linux+ Guide to Linux Certification, 2e

  30. Internet Servers:Firewalls and Proxy Services • Firewall: Protects companies from outside intruders on the Internet • Linux has firewall support built into the kernel • Proxy server: requests Internet resources such as Web sites and FTP sites on behalf of the computer inside the company Linux+ Guide to Linux Certification, 2e

  31. Internet Servers:Web Services and News Services • Web services: Web servers host information (text, pictures, music, binary data, and video) • Can also process programs known as Common Gateway Interface (CGI) scripts and provide secure connections • News services: News servers allow users to post messages in forums called newsgroups • Most Web servers do not provide means for users to communicate Linux+ Guide to Linux Certification, 2e

  32. Internet Servers: DNS Services • Computers communicating on a network need to be uniquely identified • Each computer is assigned an Internet Protocol (IP) address • Long string of numbers • Allows computers to identify and reference each other • Fully Qualified Domain Name (FQDN): Masks IP addresses with user-friendly names Linux+ Guide to Linux Certification, 2e

  33. File and Print Servers • Linux is well-suited for centrally sharing resources • More economical to share files and printers over a network • Inherently fast and light • A distribution specific to a certain task can be installed on the central server Linux+ Guide to Linux Certification, 2e

  34. Application Servers • Application server: Intermediary between a client computer and a database • Database: Organized collection of data that is arranged into tables of related information • Database Management Systems (DBMS): Set of programs designed for creation, modification, manipulation, maintenance, and access of information from databases Linux+ Guide to Linux Certification, 2e

  35. Linux+ Guide to Linux Certification, Second Edition Chapter 2 Preparing for Linux Installation

  36. Objectives • Describe common types of hardware and their features • Obtain the hardware and software information necessary to install Linux Linux+ Guide to Linux Certification, 2e

  37. Understanding Hardware:Central Processing Units (CPUs) • Core component of any computer • Also known as microprocessor or processor • Two main components: • Arithmetic logic unit (ALU): Mathematical calculations and logic-based operations executed here • Control unit (CU): Instruction code or commands loaded and carried out here Linux+ Guide to Linux Certification, 2e

  38. Understanding Hardware: CPUs (continued) • Processor architecture: Arrangement of a processor’s integral electronics • Two main processor architectures: • Complex Instruction Set Computer (CISC) • Reduced Instruction Set Computer (RISC) Linux+ Guide to Linux Certification, 2e

  39. Understanding Hardware: CPUs (continued) • Clock speed: Internal time cycle of a processor • Determines speed that processor executes commands • Measured in Megahertz (MHz) • A processor may require one cycle to complete a command or may be superscalar • Amount of information a processor can process at one time is a major factor in clock speed • Measured in binary digits (bits) • The more information that can be worked on at once, the faster data can be manipulated Linux+ Guide to Linux Certification, 2e

  40. Understanding Hardware: CPUs (continued) • Cache: Temporary store of information • Cache size and location affect a processor’s ability to calculate larger volumes of data • Level 1 (L1) cache: Cache stored in the processor itself • Level 2 (L2) cache: Cache stored in a separate computer chip • Connected to processor via high speed link • Level 3 (L3) cache: Cache stored on a separate computer chip • Connected directly to processor Linux+ Guide to Linux Certification, 2e

  41. Understanding Hardware: CPUs (continued) • Multiple processors can work together • Perform the same tasks faster • Symmetric Multi-Processing (SMP): Allows OS and memory to use both processors simultaneously for any task • ASymmetric Multi-Processing (ASMP): Each processor given a set of tasks to complete independently Linux+ Guide to Linux Certification, 2e

  42. Understanding Hardware:Physical Memory • Storage area for information that is directly wired through circuit boards to the processor • Two main categories: • Random Access Memory (RAM) • Volatile memory • Read Only Memory (ROM) Linux+ Guide to Linux Certification, 2e

  43. Understanding Hardware:Physical Memory―RAM • Requires constant supply of electricity to maintain stored information • Directly related to computer performance • Two major categories: • Dynamic RAM (DRAM) • Static RAM (SRAM) Linux+ Guide to Linux Certification, 2e

  44. Understanding Hardware:Physical Memory―RAM (continued) • Three main types of DRAM sticks: • Single In-line Memory Modules (SIMM) • No longer produced • Dual In-line Memory Modules (DIMM) • Small Outline Dual In-line Memory Modules (SODIMM) • Used in portable notebook computers and Macintosh systems Linux+ Guide to Linux Certification, 2e

  45. Understanding Hardware:Physical Memory―RAM (continued) • Three recent DIMM technologies: • Synchronous Dynamic Random Access Memory (SDRAM) • Double Data Rate Synchronous Dynamic Random Access Memory (DDR SDRAM) • Rambus Dynamic Random Access Memory (RDRAM) Linux+ Guide to Linux Certification, 2e

  46. Understanding Hardware:Physical Memory―ROM • Read-only Memory: Physical memory that can be read but not written to • Nonvolatile • Basic Input/Output System (BIOS) ROM: Stores programs used to initialize hardware components when starting computer Linux+ Guide to Linux Certification, 2e

  47. Understanding Hardware:Physical Memory―ROM Variants • Programmable Read Only Memory (PROM): Can only be written to once • Erasable Programmable Read Only Memory (EPROM): Contents can be repeatedly erased and rewritten as a whole • Electronically Erasable Programmable Read Only Memory (EEPROM): Whole or partial contents can be repeatedly erased/rewritten Linux+ Guide to Linux Certification, 2e

  48. Understanding Hardware:Disk Drives • Most information in a computer maintained using nonvolatile media, not consisting of integrated circuits • Hard disk • Floppy disk • CD-ROM, DVD • CD-RW, DVD-RW disk • Zip disk • Flash Memory Linux+ Guide to Linux Certification, 2e

  49. Understanding Hardware:Disk Drives―Hard Disk Drives • Not directly wired to the processor • Pass through a hard disk controller card • Controls flow of information to and from the hard disk drive (HDD) • Two types of controller cards: • Integrated Drive Electronics (IDE) • Also known as Advanced Technology Attachment (ATA) controllers • Small Computer System Interface (SCSI) Linux+ Guide to Linux Certification, 2e

  50. Understanding Hardware:Disk Drives―HDDs (continued) Table 2-1: IDE HDD configurations Linux+ Guide to Linux Certification, 2e

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