Information Technology INT1001 Lecture 6 Computer Software 1.

Information Technology INT1001

Lecture 6Computer Software

1

Computers Are Your Future

Tenth Edition

Chapter 4: System Software

Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 2

Software

Software can be grouped as system software or application software System software includes the

programs that assist with the proper functioning of the computer.

Application software includes the programs used to perform tasks.


System Software


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

5Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall


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.



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

communicationCopyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 7


The first function of the operating system, starting the computer, involves six steps.



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.



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.



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.



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

properlyCopyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 12


There are three types of user interfaces: Graphical user

interface (GUI) Menu-driven user

interface Command-line

user interface



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.



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

Hall 15

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.



Microsoft Windows Vista, the replacement for Windows XP, is intended for both home and professional use.



Microsoft Windows Mobile provides a user interface in a simplified Windows format for handheld devices such as smartphones and PDAs.



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

Hall 19


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.


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.



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.



Antivirus software provides protection from computer viruses.

The two most popular antivirus programs are: Norton AntiVirus McAfee VirusScan

Plus



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



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.



File compression utilities: Decrease the size

of files, resulting in faster downloads.

Create archives by storing files in a special format.



Windows Update, an operating system update service provided by Microsoft, enables users to keep their operating system current with external modifications.


Application Software: Tools for Productivity


General-Purpose Applications

Application software is any program that gives the user the ability to complete work on the computer.

General-purpose applications are the programs that enable users to complete common tasks.



General-purpose applications include: Personal productivity programs Multimedia and graphics software Internet programs Home and education programs


Tailor-Made Applications

Software designed for specific businesses or users is known as a tailor-made application.

Tailor-made applications normally cost more than general-purpose applications because of their development costs.


Tailor-Made Applications

When an application is not available, custom software, software developed for a user’s specific needs, may be necessary.

Packaged software is developed for the mass market.


Standalone Programs, Integrated Programs, & Software Suites

A fully self-contained program is called a standalone program.

Advantages: Users can purchase and install standalone

programs separately. Standalone programs function by

themselves. Disadvantages:

Standalones take up a lot of storage space. Standalones do not share resources.



Integrated programs provide all the leading productivity programs in one package.

Advantages: Integrated programs are easy to learn. Integrated programs share the same

interface.



Disadvantages: The individual modules of integrated

programs usually have fewer features than are found in standalone programs or software suites.



A software suite is an interconnected bundle of programs.

Advantages: The programs within a suite share

resources. The programs within a suite are

designed to work together. These applications share common

program code, interfaces, and drivers.



Software suites, also called office suites, usually include:

Word processing programs Spreadsheet programs Presentation graphics programs Database programs Personal information managers (PIMs)


Standalone Programs, Integrated Programs & Software Suites



Web-hosted technology is a new variety of office suite that enables users to upload files online for viewing, editing, and collaboration purposes.

Advantages: Web-hosted technology is usually free. It makes sharing files and collaboration

easier. Web-hosted technology helps avoid file-

sharing problems.Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 40

System Requirements & Software Versions

System requirements outline the minimal level of resources that a program requires.

Releases of programs are cited by a year or version number. In a version number, a decimal

number indicates a maintenance release.



Time-limited trial versions are occasionally offered for commercial programs by software companies.

Beta versions of software are sometimes available to users. Software is in the final testing stages

and may contain bugs. Access is free.



Software is kept current through software upgrading. Small fixes to software are called

patches. Large or major fixes to software are called

service packs or service releases. Software can be distributed through

the Internet, not just purchased in stores.



Documentation can be in print or downloaded from the Internet. Brief tutorials Read Me files Help files


Software Licenses & Registration

The contract included with purchased software, which permits the user to install the program on one computer, is known as a software license.

The contract that gives organizations the right to install copies of programs on a precise number of computers is known as a site license.



Commercial Software Users must purchase before using Examples:

Microsoft Office Adobe Acrobat Apple iLife

Shareware You may try software before purchasing If you like it, pay for it and continue use



Freeware Free to users as long as users do not sell it to

others

Public domain software Copyright-free software Can modify or sell

Copy-protected software Internal process prohibits making

unauthorized copiesCopyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall 47

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.



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.



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 50


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.



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 52

What You Will Learn

Understand how system software supports application software.

List the most popular types of general-purpose applications.

Discuss the advantages and disadvantages of standalone programs, integrated programs, and software suites.


What You Will Learn

Discuss the advantages of Web-hosted technology and file compatibility.

Explain the concept of software versions and software upgrades.

Understand how commercial software, shareware, freeware, and public domain software differ.


What You Will Learn

Describe the essential concepts of application software and the skills needed to use it.


What You’ve Learned System software supports

application software, the programs that give the user the ability to complete work on the computer.

General-purpose software includes personal productivity programs, multimedia and graphics software, Internet programs, and home and education software.



Types of programs available to users include standalone programs, integrated programs, and suites of personal productivity software.

Office suites, which incorporate Web-hosted technology, are gaining popularity with today’s users.



New or updated versions of software are usually cited with a version number.

Small changes to software are defined as patches, and larger changes or fixes are known as service packs or service releases.



Software can be categorized as commercial, shareware, freeware, and public domain software.

Users should learn to install applications, start applications, select options, and exit the applications to use their computers effectively.


Information Technology INT1001 Lecture 6 Computer Software 1.

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