IIT
INTRODUCTION TO INFORMATION TECHNOLOGY
BBA
SEMESTER IV
Unit – I
Introduction to Computers: Definition of computer, Characteristics and limitations of Computers,
Functional Block diagram of digital computers, Functions of Control Unit and ALU in CPU, Concept of
Primary memory (RAM & ROM) and secondary memory, Magnetic Hard disks, Magnetic Tapes, Floppy
disk, CD-ROM, Input / Output Devices.
Networks: Definition - Network types: LAN, MAN, WAN -Network Topologies: Mesh, Bus, Star, Ring,
Hybrid – Protocols.
Introduction to Computers:
Meaning of a Computer:
Computer is a machine that can solve problems by accepting data performing certain operations
and presenting the results of those operations under the direction of detailed step-by-step
instructions. Such a set of sequenced instructions, which cause a computer to perform particular
operations, is called a program. The term computer has been derived from the word “COMPUTE”
which means calculate.
Definition of a computer
Computer is an electronic device, used for performing calculations and controlling operations
that be either expressed in logical or numerical terms.
It stores and process data in binary form according to instructions given to it in a variable
program.
Computer need to be told exactly what to do and how to do to accomplish a task
It is a combination of hardware and software
Software is the set of instructions given to the computer to perform a task
The physical parts that make up computer are called hardware, which are made of circuits
and transistors
The three main operations of computer are
1) Takes in data and instructions (input)
2) works with the data (processing)
3) puts out information (output)
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Characteristics of a Computer:
The following are the main characteristics of a computer-
1. Speed: Computer is able to process the data and give the output in fractions of seconds such
that required information is available to the user on time and hence enables him to take right
decisions at the right time.
2. Accuracy: Computer is error free. There is no scope for inaccuracy in the results given by the
computer. Incorrect calculations, errors, mistake do not take place in a computer system. If
there errors they are due to the errors in the instructions given by the programmer,
inaccurate data, inconsistent data or defective programs as well as defective system designs.
Since the computer is capable of doing only what it is instructed to do, fault instructions for
data processing may lead to faulty results this is known as GIGO (Garbage in Garbage Out)
3. Reliable: Today, computer is extensively used because of their reliability. The output
generated by the computer is very reliable to the extent that the input is reliable.
4. Storage capacity: Another important characteristic of a computer is that it has brain of its
own with brilliant memory. It can accept and store any information for a long time. It stores
large amount of data and can recall information instantly. The main memory of the computer
is relatively small and holds certain amount of information. Therefore, the data is stored in
secondary memory
5. Versatile: The computer performs three basic operations. It accepts information from the
user; secondly it performs the basic arithmetic operations and logical operations and finally
generates the desired output in the desired form.
6. Automatic (Programmable): Computer is a device, which is more than a calculator. Once
instructions are given to the system it works automatically without any human intervention
until the completion of program until it meets logical instruction to terminate the job.
7. Diligent: A computer is a device, which is indefatigable (untiring) and therefore does not feel
tired nor gets distracted like a human being. All the instructions are performed at same speed
and accuracy
8. Recreation: In recent years, computers were used mainly for entertainment and amusement,
like computer games and other programs, computer animation gives life and movement to
inanimate objects. Multimedia too helped in popularizing the use of computers.
9. Networking capacity: A computer can be connected with other computers. This feature of
connectivity with other computers leads to the evolution of computer networking.
10. Compactness: Now-a-day’s size of computers has decreased o lot due to increased
technology. The laptop and Notebook computers can be taken outside.
Limitations of A Computer:
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, IIT
Like any modern technology computers is also not free from limitations-
Computer is a machine and therefore it is only a device that needs human skill to
operate.
It does not work on its own and needs set of instructions to be given.
It does not have natural intelligence and hence has to be instructed about every step
in detail.
It is not a decision maker and has to be programmed to take an action if some
conditions prevail.
Finally, it does not learn by experience unlike intelligent human beings.
Elements of a Computer:
A computer consists of three basic elements/components such as hardware, software and
memory.
Hardware:
The physical devices that make up a computer are referred to as hardware.
It includes the tangible aspects of computers and can be touched such as mouse, printers,
monitor, microphone, scanner etc.
Hardware is usually used for input and output purposes. It takes instructions from the user
from input devices such as mouse, key board etc and displays the output (after processing)
on the other hardware devices such as monitor, LCDs, scanner, printers etc.
Software:
The software of the computer includes operating system which executes all the programs and
instructions given by the user.
The computer software itself is categorized into two
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, IIT
1. System Software
It is collection of programs designed to operate, control, and extend the processing
capabilities of the computer itself. System software are generally prepared by computer
manufactures. These software products comprise of programs written in low-level languages
which interact with the hardware at a very basic level. System software serves as the interface
between hardware and the end users.
Includes the software execution by the computer itself such as Windows and DOS.
2. Application Software
Application software products are designed to satisfy a particular need of a particular
environment.
Application software may consist of a single program, such as a Microsoft's notepad for
writing and editing simple text. It may also consist of a collection of programs, often called a
software package, which work together to accomplish a task, such as a spreadsheet package.
FUNCTIONAL BLOCK DIAGRAM OF COMPUTER:
• A Computer, like a human brain, receives data and instruction, stores them and processes
the data according to the instructions given to it.
• It receives data from input devices, stores them in memory and displays them through on
an output device
ST Joseph’s Degree & PG College 4
INTRODUCTION TO INFORMATION TECHNOLOGY
BBA
SEMESTER IV
Unit – I
Introduction to Computers: Definition of computer, Characteristics and limitations of Computers,
Functional Block diagram of digital computers, Functions of Control Unit and ALU in CPU, Concept of
Primary memory (RAM & ROM) and secondary memory, Magnetic Hard disks, Magnetic Tapes, Floppy
disk, CD-ROM, Input / Output Devices.
Networks: Definition - Network types: LAN, MAN, WAN -Network Topologies: Mesh, Bus, Star, Ring,
Hybrid – Protocols.
Introduction to Computers:
Meaning of a Computer:
Computer is a machine that can solve problems by accepting data performing certain operations
and presenting the results of those operations under the direction of detailed step-by-step
instructions. Such a set of sequenced instructions, which cause a computer to perform particular
operations, is called a program. The term computer has been derived from the word “COMPUTE”
which means calculate.
Definition of a computer
Computer is an electronic device, used for performing calculations and controlling operations
that be either expressed in logical or numerical terms.
It stores and process data in binary form according to instructions given to it in a variable
program.
Computer need to be told exactly what to do and how to do to accomplish a task
It is a combination of hardware and software
Software is the set of instructions given to the computer to perform a task
The physical parts that make up computer are called hardware, which are made of circuits
and transistors
The three main operations of computer are
1) Takes in data and instructions (input)
2) works with the data (processing)
3) puts out information (output)
ST Joseph’s Degree & PG College 1
, IIT
Characteristics of a Computer:
The following are the main characteristics of a computer-
1. Speed: Computer is able to process the data and give the output in fractions of seconds such
that required information is available to the user on time and hence enables him to take right
decisions at the right time.
2. Accuracy: Computer is error free. There is no scope for inaccuracy in the results given by the
computer. Incorrect calculations, errors, mistake do not take place in a computer system. If
there errors they are due to the errors in the instructions given by the programmer,
inaccurate data, inconsistent data or defective programs as well as defective system designs.
Since the computer is capable of doing only what it is instructed to do, fault instructions for
data processing may lead to faulty results this is known as GIGO (Garbage in Garbage Out)
3. Reliable: Today, computer is extensively used because of their reliability. The output
generated by the computer is very reliable to the extent that the input is reliable.
4. Storage capacity: Another important characteristic of a computer is that it has brain of its
own with brilliant memory. It can accept and store any information for a long time. It stores
large amount of data and can recall information instantly. The main memory of the computer
is relatively small and holds certain amount of information. Therefore, the data is stored in
secondary memory
5. Versatile: The computer performs three basic operations. It accepts information from the
user; secondly it performs the basic arithmetic operations and logical operations and finally
generates the desired output in the desired form.
6. Automatic (Programmable): Computer is a device, which is more than a calculator. Once
instructions are given to the system it works automatically without any human intervention
until the completion of program until it meets logical instruction to terminate the job.
7. Diligent: A computer is a device, which is indefatigable (untiring) and therefore does not feel
tired nor gets distracted like a human being. All the instructions are performed at same speed
and accuracy
8. Recreation: In recent years, computers were used mainly for entertainment and amusement,
like computer games and other programs, computer animation gives life and movement to
inanimate objects. Multimedia too helped in popularizing the use of computers.
9. Networking capacity: A computer can be connected with other computers. This feature of
connectivity with other computers leads to the evolution of computer networking.
10. Compactness: Now-a-day’s size of computers has decreased o lot due to increased
technology. The laptop and Notebook computers can be taken outside.
Limitations of A Computer:
ST Joseph’s Degree & PG College 2
, IIT
Like any modern technology computers is also not free from limitations-
Computer is a machine and therefore it is only a device that needs human skill to
operate.
It does not work on its own and needs set of instructions to be given.
It does not have natural intelligence and hence has to be instructed about every step
in detail.
It is not a decision maker and has to be programmed to take an action if some
conditions prevail.
Finally, it does not learn by experience unlike intelligent human beings.
Elements of a Computer:
A computer consists of three basic elements/components such as hardware, software and
memory.
Hardware:
The physical devices that make up a computer are referred to as hardware.
It includes the tangible aspects of computers and can be touched such as mouse, printers,
monitor, microphone, scanner etc.
Hardware is usually used for input and output purposes. It takes instructions from the user
from input devices such as mouse, key board etc and displays the output (after processing)
on the other hardware devices such as monitor, LCDs, scanner, printers etc.
Software:
The software of the computer includes operating system which executes all the programs and
instructions given by the user.
The computer software itself is categorized into two
ST Joseph’s Degree & PG College 3
, IIT
1. System Software
It is collection of programs designed to operate, control, and extend the processing
capabilities of the computer itself. System software are generally prepared by computer
manufactures. These software products comprise of programs written in low-level languages
which interact with the hardware at a very basic level. System software serves as the interface
between hardware and the end users.
Includes the software execution by the computer itself such as Windows and DOS.
2. Application Software
Application software products are designed to satisfy a particular need of a particular
environment.
Application software may consist of a single program, such as a Microsoft's notepad for
writing and editing simple text. It may also consist of a collection of programs, often called a
software package, which work together to accomplish a task, such as a spreadsheet package.
FUNCTIONAL BLOCK DIAGRAM OF COMPUTER:
• A Computer, like a human brain, receives data and instruction, stores them and processes
the data according to the instructions given to it.
• It receives data from input devices, stores them in memory and displays them through on
an output device
ST Joseph’s Degree & PG College 4
