INTRODUCTION
Definition: A Computer is an electronic device that can perform activities that involve
Mathematical, Logical and graphical manipulations. Generally, the term is used to describe a
collection of devices that function together as a system. It performs the following three operations in
sequence.
1. It receives data & instructions from the input device.
2. Processes the data as per instructions.
3. Provides the result (output) in a desired form.
Data: It is the collection of raw facts, figures & symbols. Ex : Names of students and their marks in
different subjects listed in random order.
Information: It is the data that is processed & presented in an organized manner. Ex : When the
names of students are arranged in alphabetical order, total and average marks are calculated &
presented in a tabular form, it is information.
Program: Set of instructions that enables a computer to perform a given task.
Advantages of computers :
1. High speed: Computers have the ability to perform routine tasks at a greater speed than human
beings. They can perform millions of calculations in seconds.
2. Accuracy: Computers are used to perform tasks in a way that ensures accuracy.
3. Storage: Computers can store large amount of information. Any item of data or any instruction
stored in the memory can be retrieved by the computer at lightning speeds.
4. Automation: Computers can be instructed to perform complex tasks automatically (which
increases the productivity).
5. Diligence: Computers can perform the same task repeatedly & with the same accuracy without
getting tired.
6. Versatility: Computers are flexible to perform both simple and complex tasks.
7. Cost effectiveness: Computers reduce the amount of paper work and human effort, thereby
reducing costs.
Limitations of computers:
1. Computers need clear & complete instructions to perform a task accurately. If the
instructions are not clear & complete, the computer will not produce the required result.
2. Computers cannot think.
3. Computers cannot learn by experience.
, The computer system consists of three units:
1. Input device
2. Central Processing Unit (CPU)
3. Output device
Block diagram of a Computer:
The various functions of these units can be summarized as:
Unit Function
1. Input device: Reads information from input media and enters to the computer in a coded form
2. CPU
(a) Memory unit: Stores program and data
(b) Arithmetic Logic unit: Performs arithmetic and logical functions
(c) Control Unit: Interprets program instructions and controls the input and output devices
3. Output device: decodes information and presents it to the user
Definition: A Computer is an electronic device that can perform activities that involve
Mathematical, Logical and graphical manipulations. Generally, the term is used to describe a
collection of devices that function together as a system. It performs the following three operations in
sequence.
1. It receives data & instructions from the input device.
2. Processes the data as per instructions.
3. Provides the result (output) in a desired form.
Data: It is the collection of raw facts, figures & symbols. Ex : Names of students and their marks in
different subjects listed in random order.
Information: It is the data that is processed & presented in an organized manner. Ex : When the
names of students are arranged in alphabetical order, total and average marks are calculated &
presented in a tabular form, it is information.
Program: Set of instructions that enables a computer to perform a given task.
Advantages of computers :
1. High speed: Computers have the ability to perform routine tasks at a greater speed than human
beings. They can perform millions of calculations in seconds.
2. Accuracy: Computers are used to perform tasks in a way that ensures accuracy.
3. Storage: Computers can store large amount of information. Any item of data or any instruction
stored in the memory can be retrieved by the computer at lightning speeds.
4. Automation: Computers can be instructed to perform complex tasks automatically (which
increases the productivity).
5. Diligence: Computers can perform the same task repeatedly & with the same accuracy without
getting tired.
6. Versatility: Computers are flexible to perform both simple and complex tasks.
7. Cost effectiveness: Computers reduce the amount of paper work and human effort, thereby
reducing costs.
Limitations of computers:
1. Computers need clear & complete instructions to perform a task accurately. If the
instructions are not clear & complete, the computer will not produce the required result.
2. Computers cannot think.
3. Computers cannot learn by experience.
, The computer system consists of three units:
1. Input device
2. Central Processing Unit (CPU)
3. Output device
Block diagram of a Computer:
The various functions of these units can be summarized as:
Unit Function
1. Input device: Reads information from input media and enters to the computer in a coded form
2. CPU
(a) Memory unit: Stores program and data
(b) Arithmetic Logic unit: Performs arithmetic and logical functions
(c) Control Unit: Interprets program instructions and controls the input and output devices
3. Output device: decodes information and presents it to the user
