Introduction To Computer: BY Kiramat Rahman

INTRODUCTION TO
COMPUTER
LECTURE 4
BY
Kiramat Rahman
outline
 In this Lecture you will learn about:
 Term “Software” and its relationship with “Hardware”
 Various types of software and their examples
 Relationship among hardware, system software,
 application software, and users of a computer system
 Different ways of acquiring software
 Various steps involved in software development
 Firmware
 Middleware
 Hardware refers to the physical devices of a
 computer system.
 Software refers to a collection of programs
 Program is a sequence of instructions written in a
language that can be understood by a computer

 Software package is a group of programs that solve
a specific problem or perform a specific type of job

Relationship Between Hardware and
Software
 Both hardware and software are necessary for a computer to do

useful job.
 They are complementary to each other
 Same hardware can be loaded with different software to make a
computer system perform different types of jobs Except for
upgrades,
 hardware is normally a onetime expense, whereas software is a
continuing expense
 Upgrades refer to renewing or changing components
 like increasing the main memory, or hard disk
 capacities, or adding speakers, modems, etc.
Types of Software
 Most software can be divided into two major
categories:
 System software are designed to control the
 operation and extend the processing capability of a
computer system
 Application software are designed to solve a
 specific problem or to do a specific task
System Software
 Make the operation of a computer system more effective
and efficient
 Help hardware components work together and provide
 support for the development and execution of application
 software
 Programs included in a system software package are
 called system programs and programmers who
 prepare them are called system programmers
 Examples of system software are operating systems,
 programming language translators, utility programs, and
 communications software
Application Software
 Solve a specific problem or do a specific task
 Programs included in an application software
 package are called application programs and the
 programmers who prepare them are called
 application programmers
 Examples of application software are word
 processing, inventory management, preparation of
tax returns, banking, etc.
Logiicall Systtem Archiittectture
Ways off Acquiring Software
 Buying pre-written software
 Ordering customized software
 Developing customized software
 Downloading public-domain software
 Each of these ways of acquiring software has its
own advantages and limitations
Advantages and Limitations of
Buying Pre-written Software
 Usually costs less

 Planned activity can be started almost immediately
 Often, operating efficiency and the capability to
meet
 specific needs of user more effectively in not as
good
 for pre-written software packages as for in-house
 developed software packages
Advantages & Limitations of Ordering
Customized Software
 User need not maintain its own software

development team, which is an expensive affair
 User needs to always depend on the vendor for
carrying out
 the changes and the vendor may separately charge
for every request for change
Advantages & Limitations of Developing
Customized Software
 Easier to carry out changes in the software, if it is
developed in-house
 Developing software in-house means a major
 commitment of time, money, and resources
 In-house software development team needs to be
maintained and managed
of Downloading
Public-domain Software
 Available for free or as shareware, and are usually accompanied

 with source code
 Usually community-supported as author does not support users
 directly
 Can be downloaded and used immediately
 They may not be properly tested before release
 Open Source Software (OSS) are becoming popular due to:
 Allows any user to download, view, modify, and redistribute
 User can fix bugs or change software to suit needs
 Copyright is protected for both original and subsequent
 authors
 Not all open source software are free and vise-verse
Software Development Steps
 Developing a software and putting it to use is a
complex process and involves following steps:
 Analyzing the problem at hand and planning the
 program(s) to solve the problem
 Coding the program(s)
 Testing, debugging, and documenting the program(s)
 Implementing the program(s)
 Evaluating and maintaining the program(s)
Firmware
 Firmware is software substituted for hardware and
stored in read-only memory
 Firmware technology has enabled production of
various types of smart machines having
microprocessor chips with embedded software
Middleware
 Basic idea is to have a separate software layer to:
 Act as “glue” between client and server parts of
 Application Provide programming abstraction
 Encourages three-tier software architecture against
two tier
 popularized by Server-Client architecture
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INTRODUCTION TO

 Software refers to a collection of programs

 Program is a sequence of instructions written in a

language that can be understood by a computer

a specific problem or perform a specific type of job

 Both hardware and software are necessary for a computer to do

 Usually costs less

 User need not maintain its own software

 Available for free or as shareware, and are usually accompanied

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