1GMS-VU : Module 2

Introduction to Information and Communication

Technologies

Module 2Module 2Computer Software Computer Software

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Scope What is software? What are the types of software? How is software created? What are some problems in using software? How do you ensure security of the system

and data? What are future trends in software

development?

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Learning OutcomesBy the end of this lesson, you should be able to:

1. Define the functions of software in a computer system

2. Identify the different types of software3. List different types of operating systems and

application software4. Identify steps in creating software5. Identify problems in using software6. Describe the ways to ensure security of the

system and data7. Identify general trends in software development

4GMS-VU : Module 2

What is software? A computer system is generally composed

of hardware and software. Hardware makes up the physical

components. Software makes up the set of instructions

for the computer. Without software, the computer will not be able to perform the tasks required.

Sometimes software is called a computer program.

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What are the types of software?

There are two sets of instructions that a computer must follow:

System software such as DOS, Windows, Linux, Unix, and Mac OS

Application software such as those used for word processing, spreadsheets, or library management

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System Software An organized collection of system programs which

serve as the interface between the computer hardware and the user application

It manages the hardware resources: Operating System

CPU management to facilitate sharing execution time of processes

Memory management to allocate memory resources dynamically

I/O management to handle reading and writing devices

Compiler/Interpreter Utilities

CPU

Memory

I/O

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Examples of Operating Systems

Disk Operating System (DOS)Microsoft WindowsMac OSLINUXUNIXOther Proprietary OS

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A generic term describing any operating system that is loaded from disk devices

It is not a user friendly OS since users need to memorize commands and issue them by typing line by line, known as command line interface.

Very few end users use DOS nowadays.

Disk Operating Systems (DOS)

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Microsoft Windows A Graphical User Interface (GUI), which was

originally run on DOS (Windows 3.x), that allows multitasking or the ability to run several programs at the same time

Examples: Microsoft Windows 95 Microsoft Windows 98 Microsoft Windows 2000 Microsoft Windows XP

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Application Software A set of instructions designed to perform a

specific task such as word processing, accounting, cataloguing, library management, animation, etc.

The type of the software depends on the application

General purpose office softwareBusiness softwareSpecial purpose and other software

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General Purpose Office Software Word processing: e.g. MS Word Spreadsheets: e.g. MS Excel Database management

systems: e.g. MS Access, SQL Presentation/Graphics: e.g. MS

PowerPoint, Adobe Photoshop Software suite: e.g. MS Office

*MS stands for Microsoft

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Business Software A set of software used for

business application such as software for banking, e-Commerce, etc.

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Special purpose software and other software Desktop publishing software: e.g. MS Publisher Imaging and drawing: e.g. Corel Draw File management: e.g. CDS/ISIS, INMAGIC Library management software: e.g. Athena,

VTLS, INNOPAC, Library Solutions Other Software: e.g. Statistics and

registration software, etc.

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How is software created? Software Development Process

2.0 Software Design

1.0 Software Analysis

3.0 Programming/Coding4.0 Compiling

5.0 Testing and Debugging

6.0 Implementing and maintenance

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1.0 Software Analysis

•To identify problems and user requirements

2.0 Software Design

•To illustrate what the software will do and what output will be generated

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3.0 Programming/Coding

•To create the software by translating specifications and requirements into program instructions

4.0 Compiling

•To translate program instructions into machine language

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5.0 Testing and Debugging

•To examine whether the software is error free and produces the intended results

6.0 Implementing and Maintenance

•To install and operate the software efficiently

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Programming Languages

Programming languages are used to write software. Some of these are: Low level languages

Assembly High level languages

COBOL FORTRAN C++ Pascal Visual Basic

Programming languages for the Internet Perl Java HTML XML

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What are problems in using software?

Programming languages Character sets Malicious Software

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Problems caused by programming languages Programming languages are usually in English. Applications usually use the English language

and the Roman alphabet. Problems arise when the user is non-English

and/or is using non-Roman script.

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Problems caused by different characters sets

Computers use character sets stored in binary codes.

Different scripts use different character sets.

Computers must know which writing system/character set they are dealing with.

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Problems caused by malicious software

Computer Virus Worm Trojan Horse

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A program or a code that gains access without the users’ knowledge and/or perform actions not intended by the user, often damaging data and sometimes the whole system in the process.

Viruses are activated once unknowing users run, open, view or copy the file containing it.

The action that will trigger the virus to deliver its “payload” depends on the type of virus that infected the file.

Computer Virus

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Characteristics of a virus A self-replicating program whose main purpose is

to propagate itself to as many places as possible Self-propagating by modifying another program to

include itself by an act of a user, e.g. opening/ viewing files unknowing that they are infected and/or copying/transferring files from one system to another through diskettes, file transfer, e-mail, the internet and other means…

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Worm

A program that replicates and propagates itself without any action from the user

This differentiates it from a virus that needs user action in order to replicate.

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A Trojan horse contains hidden functions that, while running, may destroy files or create a “back door” allowing an intruder to access the system.

A Trojan horse, unlike a virus, does not spread by itself but can be as destructive, depending on the intentions of the intruder.

Trojan Horse

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How do you ensure security of the system and data? Back-up your system and your data regularly by

using CD-R, CD-RW, diskettes, tapes, or another hard disk.

Use firewalls, encryption and other security measures to protect data, computer systems and networks from intrusion and attacks done through the Internet.

Protect yourself from malicious software: Virus/Worm/Trojan Horse.

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Protect yourself from Protect yourself from viruses, worms and viruses, worms and Trojan horsesTrojan horses Refrain from running any program or opening any

file from untrusted sources. Scan floppy diskettes and CD-ROMs before using. Install a virus shield to automatically check

diskettes and CDs. Get an updated version of a virus scan program. Always check you hard disk for possible infection,

if you are connected to the Internet. Use diskettes only after they have been scanned.

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What are future trends in software development? More user friendly

More customized More Web enabled More flexible/compatible More sophisticated

programming languages functions