Transcript Linux+ Guide to Linux Certification

Linux+ Guide to Linux
Certification, Second Edition
Chapter 1
Introduction to Linux
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
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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
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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
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Operating Systems (continued)
Figure 1-1: The role of operating system software
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Operating Systems (continued)
• Graphical user interface (GUI): Component of an
OS that provides a user-friendly interface
• System services: Applications that handle systemrelated tasks
– Printing
– Scheduling programs
– Network access
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Operating Systems (continued)
Figure 1-2: A Linux graphical user interface
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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
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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
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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
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Identifying Kernel Versions (continued)
Table 1-1: Latest revisions of common Linux kernels
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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
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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
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Licensing Linux (continued)
Table 1-2: Software types
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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
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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
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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
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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
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Linux Advantages:
Cost Reduction
Table 1-3: Calculating the total cost of ownership
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The History of Linux
Figure 1-4: Timeline of UNIX and Linux development
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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
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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
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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
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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
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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)
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Linux Distributions (continued)
Figure 1-5: The GNOME Desktop
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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
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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
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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
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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
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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
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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
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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
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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
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Linux+ Guide to Linux
Certification, Second Edition
Chapter 2
Preparing for Linux Installation
Objectives
• Describe common types of hardware and their
features
• Obtain the hardware and software information
necessary to install Linux
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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
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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)
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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
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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
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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
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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)
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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)
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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
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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)
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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
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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
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Understanding Hardware:
Disk Drives
• Most information in a computer maintained using
nonvolatile media, not consisting of integrated
circuits
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Hard disk
Floppy disk
CD-ROM, DVD
CD-RW, DVD-RW disk
Zip disk
Flash Memory
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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)
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Understanding Hardware:
Disk Drives―HDDs (continued)
Table 2-1: IDE HDD configurations
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Understanding Hardware:
Disk Drives―HDDs (continued)
• Partitions: Small, manageable sections of a hard
drive
• Filesystems: Specify how data should reside on the
hard disk itself
– A partition must be formatted with a filesystem
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Understanding Hardware:
Disk Drives―HDDs (continued)
• Primary partitions: Major unique and separate HDD
divisions
• Extended partitions: Partitions that can be further
subdivided into logical drives
• Master Boot Record (MBR): Table of all partition
information for a hard disk
– Stored outside of all partitions
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Understanding Hardware:
Disk Drives―HDDs (continued)
Table 2-2: Example partitioning scheme
for a primary master IDE HDD
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Understanding Hardware: Disk
Drives―Other Information Storage
Devices
• Removable media: Information storage media that
can be removed from the computer
– Transferable between computers
• Floppy disks: Store information electromagnetically
– Used in floppy disk drives
• Zip disks: Similar to floppy disks
– Can store much more information
– Used in zip drives
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Understanding Hardware: Disk
Drives―Other Information Storage
Devices (continued)
• DVDs and CD-ROMs: Use lasers to read reflected
light pulses
– Greater data transfer speed
– Larger storage capacity
– More resistance to data loss than floppy disks or ZIP
disks
• Flash memory drives: Use EEPROM chips to store
information
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Understanding Hardware: Mainboards
and Peripheral Components
• Bus: Pathway information takes from one hardware
device to another via a mainboard
• Mainboard (also called a motherboard): Circuit
board that connects all other hardware components
together via slots or ports on the circuit board
• Peripheral components: Attach to the mainboard of
a computer
– e.g., video cards, sound cards, and network
interface cards (NICs)
– Connected via an Input/Output bus represented by
different slots or ports on the mainboard
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Understanding Hardware: Mainboards
and Peripheral Components
(continued)
• Three common slots for peripheral devices:
– Industry Standard Architecture (ISA): Information
transfer at 8 MHz
– Peripheral Component Interconnect (PCI):
Information transfer at 33 MHz
• Can use Direct Memory Access (DMA)
– Accelerated Graphics Port (AGP): Information
transfer over 66 MHz
• Designed for video card peripherals
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Understanding Hardware: Mainboards
and Peripheral Components
(continued)
Figure 2-1: Mainboard components
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Understanding Hardware: Mainboards
and Peripheral Components
(continued)
• Other peripherals may have external connections
to mainboard
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PS/2
COM (Serial)
LPT
USB
IEEE1394 (Firewire)
PCMCIA
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Understanding Hardware: Mainboards
and Peripheral Components
(continued)
• Personal Computer Memory Card International
Association (PCMCIA) ports: Allow a small card to
be inserted into the computer with electronics
necessary to provide certain functionality
• Advanced Power Management (APM): BIOS
feature that shuts off power to unused peripheral
devices
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Understanding Hardware: Mainboards
and Peripheral Components
(continued)
• Interrupt Request Line (IRQ): Specifies a unique
channel from a device to the CPU
• Input/Output (IO) address: Small working area of
RAM where CPU can pass information to and
receive information from a device
• Plug-and-Play (PnP): OS and peripheral devices
that automatically assign the correct IRQ, I/O
address, and DMA settings
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Understanding Hardware: Video
Adapter Cards and Monitors
• Video adapter cards: Provide graphical display
when connected to a monitor
– Commonly referred to as video cards
• Resolution: Total number of pixels that can be
displayed on a computer video screen
• Color depth: Total set of colors that can be
displayed on a computer video screen
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Understanding Hardware: Video
Adapter Cards and Monitors
(continued)
Table 2-3: Memory requirements for
screen resolution and color depths
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Understanding Hardware: Video
Adapter Cards and Monitors
(continued)
• Refresh rate: Rate at which information displayed
on a video screen is refreshed
– Measured in Hertz (Hz)
– Two types of refresh rates:
• HSync (horizontal refresh)
• VSync (vertical refresh)
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Understanding Hardware:
Keyboards and Mice
• Facilitates user input and direction
• Variety of ways to connect to motherboard
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Serial port
Large circular AT 5-pin connector
Small circular PS/2 6-pin connector
USB connection
Wireless or radio connection
• Check hardware components against a Hardware
Compatibility List (HCL)
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Gathering Preinstallation Information
Table 2-4: Red Hat 7.2 hardware requirements
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Gathering Preinstallation Information
(continued)
Table 2-5: Sample pre-installation checklist
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Gathering Preinstallation Information
(continued)
Table 2-5 (continued): Sample pre-installation checklist
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Gathering Hardware Information
• Tools and resources to check hardware against a
preinstallation checklist:
– Computer manuals
– Windows System Information tool (if Windows
already installed)
– Windows Device Manager (if Windows already
installed)
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Gathering Hardware Information
(continued)
Figure 2-2: The Windows System Information tool
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Gathering Hardware Information
(continued)
Figure 2-3: The Windows Device Manager
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Gathering Hardware Information
(continued)
Figure 2-4: The Windows Display applet
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Gathering Hardware Information
(continued)
Figure 2-5: System Power-On Self Test (POST)
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Gathering Hardware Information
(continued)
Figure 2-6: BIOS Setup Utility
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Gathering Software Information
• Identifying system network configuration:
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Hostname
IP address
Netmask
Gateway
DNS servers
• Resolve FQDNs
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Gathering Software Information
(continued)
• Dynamic Host Configuration Protocol (DHCP)
server: Server on network providing IP
configuration to requesting computers
– If selected during installation, Linux will attempt to
get IP settings from a DHCP server on the network
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Gathering Software Information
(continued)
Table 2-6: Common Linux packages
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Gathering Software Information
(continued)
Table 2-6 (continued): Common Linux packages
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