Computers Are Your Future Tenth Edition Chapter 4: System Software Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall1.
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Computers Are Your Future
Tenth Edition
Chapter 4: System Software
Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 1
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All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic,
mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Printed in the United States of America.
Copyright © 2009 Pearson Education, Inc. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice HallPublishing as Prentice Hall
What You Will Learn
List the two major components of system software.
Explain why a computer needs an operating system.
List the five basic functions of an operating system.
Explain what happens when you turn on a computer.
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What You Will Learn
List the three major types of user interfaces.
Discuss the strengths and weaknesses of the most popular operating systems.
List the seven system utilities that are considered to be essential.
Discuss data backup procedures.Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 4
What You Will Learn
Understand troubleshooting techniques and determine probable solutions to any operating system problems you may encounter.
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System Software
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OPERATING SOFTWARE
Every computer from smallest notebook to the largest supercomputer,has an operating system....
System software works with end users, application software, and computer hardware to handle technical details.
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The Operating System
System software consists of all the programs that enable the computer and its peripheral devices to function smoothly.
System software is divided into two main categories: The operating system (OS) System utility programs
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The Operating System
Management of the resources of a computer are performed by the computer’s operating system (OS).
The coordination of the functions of a computer’s hardware is the prime responsibility of the operating system.
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The Operating System
The five basic functions carried out by the operating system are: Starting the computer Managing applications Managing memory Handling input and output device messages Providing a user interface for communication
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The Operating System
The first function of the operating system, starting the computer, involves six steps.
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The Operating System
The first step in starting a computer is loading the BIOS (Basic Input/Output System) instructions into memory, which provides the computer with the ability to accept keyboard input and show information on the monitor.
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BIOS
In the BIOS UI, a user can:configure hardwareset the system clockenable or disable system componentsselect which devices are eligible to be a potential boot deviceset various password prompts, such as a password for securing access to the BIOS UI functions itself and preventing malicious users from booting the system from unauthorized peripheral devices.
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BIOS
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The Operating System
The second step in starting a computer is conducting the power-on self-test (POST) to confirm that both the computer and its peripheral devices are working properly. A beep will sound, an error message will
appear on the monitor, and the computer will stop should any part of the POST fail.
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POST
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The Operating System
The third step in starting a computer is loading the operating system. The BIOS looks for the operating system after
the successful completion of the POST. When the BIOS finds the operating system, the
operating system’s kernel, the central portion of the operating system, is loaded into memory.
The operating system then starts the process of loading the system configuration information.Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 17
LOADING OPERATING SYTEM
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The Operating System
The fourth step in starting a computer is system configuration. The registry, a database, stores the
information relating to software and peripheral configuration, background graphics, and mouse settings.
The operating system checks that drivers, utility programs required for the proper functioning of peripheral devices, are installed.
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SYSTEM CONFIGURATION
Define what a system is composed of
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The Operating System
The fifth step in starting a computer is loading system utilities. System utilities, such as antivirus
software and speaker volume control, are loaded after all system hardware is identified and configured by the operating system.
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The Operating System
The sixth step in starting a computer is authenticating users. After the operating system is loaded,
the user may be asked for an authentication/login, a user name and password, to prove that he or she is authorized.
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The Operating System
The operating system’s second function is managing applications. Single-task operating systems
from the past were only able to run one application at a time.
Today’s multitasking operating systems permit more than one application to be used at a time.
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The Operating System
When multitasking, users perceive active and inactive applications as the foreground application and background application, respectively.
Preemptive multitasking prevents application monopolization of the CPU.
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Preemptive multitasking
Preemptive multitasking allows the computer system to more reliably guarantee each process a regular "slice" of operating time.
If one program becomes unstable or stops working , the operating system and other application will continue to run
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The Operating System
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The Operating System
The operating system’s third function is managing memory. The operating system attempts to
allocate memory, RAM, to each program being run without interference.
Through the use of virtual memory, where a portion of the hard disk is used as an extension of RAM, additional memory is available.
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RAM
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Virtual memory For example, if you load the operating system, an
e-mail program, a Web browser and word processor into RAM simultaneously, 32 megabytes is not enough to hold it all. If there were no such thing as virtual memory, then once you filled up the available RAM your computer would have to say, "Sorry, you can not load any more applications. Please close another application to load a new one." With virtual memory, what the computer can do is look at RAM for areas that have not been used recently and copy them onto the hard disk. This frees up space in RAM to load the new application.
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The Operating System
Pages, set amounts of data or program instructions, are temporarily stored in a swap file, a special hard disk file, when RAM is full.
The process of transferring files between RAM and the hard disk is known as paging.
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The Operating System
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The Operating System
The operating system’s fourth function is managing input and output. The operating system uses drivers,
programs containing information regarding specific computer input and output devices, to communicate with those devices.
Interrupts, signals created by input and output devices, notify the operating system when an action has been taken.
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The Operating System
The operating system’s fifth function is providing a user interface.
The user interface allows the user to: Start application programs Manage storage devices Safely shut down the computer
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The Operating System
There are three types of user interfaces: Graphical user
interface (GUI) Menu-driven user
interface Command-line
user interface
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The Operating System
The graphical user interface uses graphics called icons, small images that represent various computer resources, to initiate actions.
These icons appear on the desktop, the work area that is created once the operating system has been loaded into memory.
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The Operating System
The menu-driven user interface provides text-based menus, which display appropriate user options that are available.
The command-line user interface forces the user to type commands line by line to instruct the operating system about the desired action(s) to be taken.Copyright © 2009 Pearson Education, Inc. Publishing as Prentice
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Exploring Popular Operating Systems
Operating systems are usually already installed on a computer when you purchase it.
The most commonly supplied operating system is Microsoft Windows.
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Exploring Popular Operating Systems
Microsoft Windows Vista, the replacement for Windows XP, is intended for both home and professional use.
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Windows 7 is the most recent Microsoft OS
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Exploring Popular Operating Systems
Microsoft Windows Server 2008 is intended for use in the corporate environment to support client/server systems.
Microsoft Windows Server 2008 provides benefits in the areas of security, enhanced Web server capabilities, administration, and virtualization.
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Exploring Popular Operating Systems
Microsoft Windows Mobile provides a user interface in a simplified Windows format for handheld devices such as smartphones and PDAs.
The last version is "Windows Mobile 6.5.5"
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Exploring Popular Operating Systems
The Mac OS used on Macintosh personal computers is favored by its users for the operating system’s security, stability, and simplicity.
UNIX was developed to work in a secure computer network, but unfortunately, its many versions are not compatible and can be hard to use.Copyright © 2009 Pearson Education, Inc. Publishing as Prentice
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Exploring Popular Operating Systems
Linux is a powerful open source operating system that is freely available to any user.
MS-DOS (DOS), a disk operating system, is a command-line user interface operating system that is not user friendly.
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System Utilities: Housekeeping Tools
System utilities (utility programs) are system software programs that are essential to effective management of the computer system.
System utilities include software that performs such tasks as backing up files, providing antivirus protection, and compressing files.
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System Utilities: Housekeeping Tools
Backup software duplicates data found on the hard disk to a backup device. Full backups include all files and
data. Incremental backups include only
those files changed or added since the previous backup.
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FULL BACKUP Typically full backups are only done
once a week and are part of an overall backup plan. Sometimes a full backup is done after a major change of the data on the disk, such as an operating system upgrade or software install. The relatively long intervals between backups mean that if something goes wrong, a lot of data is going to be lost. That's why it is wise to back up data between full backups.
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INCREMENTAL BACKUP Incremental backups also back up only the
changed data, but they only back up the data that has changed since the last backup
If you do an incremental backup on Tuesday, you only back up the data that changed since the incremental backup on Monday. The result is a much smaller, faster backup. The characteristic of incremental backups is the shorter the time interval between backups, the less data to be backed up
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System Utilities: Housekeeping Tools
Antivirus software provides protection from computer viruses.
The two most popular antivirus programs are: Norton AntiVirus McAfee VirusScan
Plus
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System Utilities: Housekeeping Tools
The utility software used to organize and manage data on your disk is called the file manager.
The file manager enables you to: Copy files Determine how and where files are
stored Delete files
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System Utilities: Housekeeping Tools
Disk scanning programs find and resolve problems that result from disk file storage.
Disk cleanup utilities remove unnecessary files, which results in saving space.
Disk defragmentation programs reorganize stored data in a more efficient manner.
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DISK SCANNING
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System Utilities: Housekeeping Tools
File compression utilities: Decrease the size
of files, resulting in faster downloads.
Create archives by storing files in a special format.
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System Utilities: Housekeeping Tools
Windows Update, an operating system update service provided by Microsoft, enables users to keep their operating system current with external modifications.
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System Utilities: Housekeeping Tools
Troubleshooting tips Keep a boot disk (emergency
disk) to load the operating system during times of emergency.
Use Microsoft’s Help and Support feature, provided with Microsoft Windows, for assistance.
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What You’ve Learned
System software is made up of two main parts: the operating system and system utilities.
Computers need software to work. The operating system coordinates the functions of hardware and supports the application software.
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What You’ve Learned
The operating system has five functions: starting the computer, managing applications, managing memory, handling messages from input and output devices, and providing an interface for communication.
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What You’ve Learned
A six-step process occurs each time you start or restart a computer.
There are three types of user interfaces: graphical user interfaces (GUIs), menu-driven user interfaces, and command-line user interfaces.Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 57
What You’ve Learned
For personal computers, Microsoft Windows and Mac OS X are the two major operating systems.
System utilities include such programs as backup software, file managers, and file compression utilities.
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What You’ve Learned
Backup procedures should include a full backup, followed by periodic incremental backups.
Troubleshooting skills are required when you use a computer. Do only what you feel comfortable doing, then enlist the help of a professional.Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 59
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