Computer Notes Unit 1
Being a modern-day kid you must have used, seen, or read about computers. This is because
they are an integral part of our everyday existence. Be it school, banks, shops, railway stations,
hospital or your own home, computers are present everywhere, making our work easier and
faster for us. As they are such integral parts of our lives, we must know what they are and how
they function. Let us start with defining the term computer formally.
The literal meaning of computer is a device that can calculate. However, modern computers can
do a lot more than calculate.
A computer is an electronic device that receives input, stores or processes the input as per user
instructions and provides output in desired format. Computers have become an integral part of
our lives because they can accomplish easy tasks repeatedly without getting bored and complex
ones repeatedly without committing errors.
Input
-Process-Output Model
Computer input is called data and the output obtained after processing it, based on user’s
instructions is called information. Raw facts and figures which can be processed using
arithmetic and logical operations to obtain information are called data.
The processes that can be applied to data are of two types −
Arithmetic operations − Examples include calculations like addition, subtraction,
differentials, square root, etc.
Logical operations − Examples include comparison operations like greater than, less
than, equal to, opposite, etc.
The corresponding figure for an actual computer looks something like this −
,The basic parts of a computer are as follows −
Input Unit − Devices like keyboard and mouse that are used to input data and
instructions to the computer are called input unit.
Output Unit − Devices like printer and visual display unit that are used to provide
information to the user in desired format are called output unit.
Control Unit − As the name suggests, this unit controls all the functions of the
computer. All devices or parts of computer interact through the control unit.
Arithmetic Logic Unit − This is the unit where all arithmetic operations and logical
operations take place.
Memory − All input data, instructions and data interim to the processes are stored in the
memory. Memory is of two types – primary memory and secondary memory. Primary
memory resides within the CPU whereas secondary memory is external to it.
Control unit, arithmetic logic unit and memory are together called the central processing
unit or CPU. Computer devices like keyboard, mouse, printer, etc. that we can see and touch
are the hardware components of a computer. The set of instructions or programs that make the
computer function using these hardware parts are called software. We cannot see or touch
software. Both hardware and software are necessary for working of a computer.
Characteristics of Computer
Following are certain advantages of computers.
High Speed
Computer is a very fast device.
It is capable of performing calculation of very large amount of data.
The computer has units of speed in microsecond, nanosecond, and even the picosecond.
It can perform millions of calculations in a few seconds as compared to man who will
spend many months to perform the same task.
Accuracy
In addition to being very fast, computers are very accurate.
The calculations are 100% error free.
, Computers perform all jobs with 100% accuracy provided that the input is correct.
Storage Capability
Memory is a very important characteristic of computers.
A computer has much more storage capacity than human beings.
It can store large amount of data.
It can store any type of data such as images, videos, text, audio, etc.
Diligence
Unlike human beings, a computer is free from monotony, tiredness, and lack of
concentration.
It can work continuously without any error and boredom.
It can perform repeated tasks with the same speed and accuracy.
Versatility
A computer is a very versatile machine.
A computer is very flexible in performing the jobs to be done.
This machine can be used to solve the problems related to various fields.
At one instance, it may be solving a complex scientific problem and the very next
moment it may be playing a card game.
Reliability
A computer is a reliable machine.
Modern electronic components have long lives.
Computers are designed to make maintenance easy.
Automation
Computer is an automatic machine.
Automation is the ability to perform a given task automatically. Once the computer
receives a program i.e., the program is stored in the computer memory, then the program
and instruction can control the program execution without human interaction.
Reduction in Paper Work and Cost
The use of computers for data processing in an organization leads to reduction in paper
work and results in speeding up the process.
As data in electronic files can be retrieved as and when required, the problem of
maintenance of large number of paper files gets reduced.
Though the initial investment for installing a computer is high, it substantially reduces
the cost of each of its transaction.
Upgradation
Computers can be upgraded (hardware/software) to improve performance or add new
capabilities.
Communication
Computers can communicate with other devices over networks enabling data sharing and
remote access.
, Resource Sharing –Data & information can be shared among group of computers thus
creating large information & knowledge base.
Disadvantages of Computers
Following are certain disadvantages of computers.
No I.Q.
A computer is a machine that has no intelligence to perform any task.
Each instruction has to be given to the computer.
A computer cannot take any decision on its own.
Dependency
It functions as per the user’s instruction, thus it is fully dependent on humans.
Environment
The operating environment of the computer should be dust free and suitable.
No Feeling
Computers have no feelings or emotions.
It cannot make judgment based on feeling, taste, experience, and knowledge unlike
humans.
1. Health Issues
Eye strain and headaches from prolonged screen use (Computer Vision Syndrome).
Back and neck pain due to poor posture.
Repetitive strain injuries (RSI) like carpal tunnel syndrome from keyboard/mouse use.
Physical inactivity, leading to obesity and related issues.
🔐 2. Security Risks
Cyberattacks like hacking, phishing, and malware.
Data breaches that can expose sensitive personal or organizational information.
Identity theft through compromised login credentials.
📉 3. Dependency and Overreliance
People become overly dependent on computers for basic tasks.
Reduced critical thinking and memory due to constant internet access.
Students may rely too much on technology instead of learning foundational skills.
Being a modern-day kid you must have used, seen, or read about computers. This is because
they are an integral part of our everyday existence. Be it school, banks, shops, railway stations,
hospital or your own home, computers are present everywhere, making our work easier and
faster for us. As they are such integral parts of our lives, we must know what they are and how
they function. Let us start with defining the term computer formally.
The literal meaning of computer is a device that can calculate. However, modern computers can
do a lot more than calculate.
A computer is an electronic device that receives input, stores or processes the input as per user
instructions and provides output in desired format. Computers have become an integral part of
our lives because they can accomplish easy tasks repeatedly without getting bored and complex
ones repeatedly without committing errors.
Input
-Process-Output Model
Computer input is called data and the output obtained after processing it, based on user’s
instructions is called information. Raw facts and figures which can be processed using
arithmetic and logical operations to obtain information are called data.
The processes that can be applied to data are of two types −
Arithmetic operations − Examples include calculations like addition, subtraction,
differentials, square root, etc.
Logical operations − Examples include comparison operations like greater than, less
than, equal to, opposite, etc.
The corresponding figure for an actual computer looks something like this −
,The basic parts of a computer are as follows −
Input Unit − Devices like keyboard and mouse that are used to input data and
instructions to the computer are called input unit.
Output Unit − Devices like printer and visual display unit that are used to provide
information to the user in desired format are called output unit.
Control Unit − As the name suggests, this unit controls all the functions of the
computer. All devices or parts of computer interact through the control unit.
Arithmetic Logic Unit − This is the unit where all arithmetic operations and logical
operations take place.
Memory − All input data, instructions and data interim to the processes are stored in the
memory. Memory is of two types – primary memory and secondary memory. Primary
memory resides within the CPU whereas secondary memory is external to it.
Control unit, arithmetic logic unit and memory are together called the central processing
unit or CPU. Computer devices like keyboard, mouse, printer, etc. that we can see and touch
are the hardware components of a computer. The set of instructions or programs that make the
computer function using these hardware parts are called software. We cannot see or touch
software. Both hardware and software are necessary for working of a computer.
Characteristics of Computer
Following are certain advantages of computers.
High Speed
Computer is a very fast device.
It is capable of performing calculation of very large amount of data.
The computer has units of speed in microsecond, nanosecond, and even the picosecond.
It can perform millions of calculations in a few seconds as compared to man who will
spend many months to perform the same task.
Accuracy
In addition to being very fast, computers are very accurate.
The calculations are 100% error free.
, Computers perform all jobs with 100% accuracy provided that the input is correct.
Storage Capability
Memory is a very important characteristic of computers.
A computer has much more storage capacity than human beings.
It can store large amount of data.
It can store any type of data such as images, videos, text, audio, etc.
Diligence
Unlike human beings, a computer is free from monotony, tiredness, and lack of
concentration.
It can work continuously without any error and boredom.
It can perform repeated tasks with the same speed and accuracy.
Versatility
A computer is a very versatile machine.
A computer is very flexible in performing the jobs to be done.
This machine can be used to solve the problems related to various fields.
At one instance, it may be solving a complex scientific problem and the very next
moment it may be playing a card game.
Reliability
A computer is a reliable machine.
Modern electronic components have long lives.
Computers are designed to make maintenance easy.
Automation
Computer is an automatic machine.
Automation is the ability to perform a given task automatically. Once the computer
receives a program i.e., the program is stored in the computer memory, then the program
and instruction can control the program execution without human interaction.
Reduction in Paper Work and Cost
The use of computers for data processing in an organization leads to reduction in paper
work and results in speeding up the process.
As data in electronic files can be retrieved as and when required, the problem of
maintenance of large number of paper files gets reduced.
Though the initial investment for installing a computer is high, it substantially reduces
the cost of each of its transaction.
Upgradation
Computers can be upgraded (hardware/software) to improve performance or add new
capabilities.
Communication
Computers can communicate with other devices over networks enabling data sharing and
remote access.
, Resource Sharing –Data & information can be shared among group of computers thus
creating large information & knowledge base.
Disadvantages of Computers
Following are certain disadvantages of computers.
No I.Q.
A computer is a machine that has no intelligence to perform any task.
Each instruction has to be given to the computer.
A computer cannot take any decision on its own.
Dependency
It functions as per the user’s instruction, thus it is fully dependent on humans.
Environment
The operating environment of the computer should be dust free and suitable.
No Feeling
Computers have no feelings or emotions.
It cannot make judgment based on feeling, taste, experience, and knowledge unlike
humans.
1. Health Issues
Eye strain and headaches from prolonged screen use (Computer Vision Syndrome).
Back and neck pain due to poor posture.
Repetitive strain injuries (RSI) like carpal tunnel syndrome from keyboard/mouse use.
Physical inactivity, leading to obesity and related issues.
🔐 2. Security Risks
Cyberattacks like hacking, phishing, and malware.
Data breaches that can expose sensitive personal or organizational information.
Identity theft through compromised login credentials.
📉 3. Dependency and Overreliance
People become overly dependent on computers for basic tasks.
Reduced critical thinking and memory due to constant internet access.
Students may rely too much on technology instead of learning foundational skills.
