Transcript Introduction to Information and Communication Technologies

Introduction to Information and Communication Technologies
Module 2
Computer Software
GMS-VU : Module 2
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Scope
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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 Outcomes
By 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 software
3. List different types of operating systems and
application software
4. Identify steps in creating software
5. Identify problems in using software
6. Describe the ways to ensure security of the
system and data
7. Identify general trends in software development
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What is software?
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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.
GMS-VU : Module 2
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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
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An organized collection of system programs which
serve as the interface between the computer
hardware and the user application
CPU
It manages the hardware resources:
 Operating System
 CPU management to facilitate
sharing execution time of processes
 Memory management to allocate
Memory
memory resources dynamically
 I/O management to handle
reading and writing devices
 Compiler/Interpreter
I/O
 Utilities
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Examples of Operating Systems
Disk Operating System (DOS)
Microsoft Windows
Mac OS
LINUX
UNIX
Other Proprietary OS
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Disk Operating Systems (DOS)
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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.
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Microsoft Windows
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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
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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 software
 Business software
 Special purpose and other software
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General Purpose Office Software
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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
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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
1.0 Software Analysis
6.0 Implementing and
maintenance
5.0 Testing and
Debugging
4.0 Compiling
2.0 Software
Design
3.0 Programming/
Coding
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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:
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Low level languages
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Assembly
High level languages
COBOL
 FORTRAN
 C++
 Pascal
 Visual Basic
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Programming languages
for the Internet
Perl
 Java
 HTML
 XML
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What are problems in
using software?
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Programming languages
Character sets
Malicious Software
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Problems caused by
programming languages
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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
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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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Computer Virus
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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.
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Characteristics of a virus
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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
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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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Trojan Horse
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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.
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How do you ensure security of the
system and data?
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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 viruses,
worms and Trojan horses
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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?
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More user friendly
More customized
More Web enabled
More flexible/compatible
More sophisticated
 programming
languages
 functions
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