What is Computer?
A computer is a programmable electronic device that accepts raw data as input and processes it with
a set of instructions (a program) to produce the result as output. It renders output just after
performing mathematical and logical operations and can save the output for future use. It can process
numerical as well as non-numerical calculations. The term "computer" is derived from the Latin word
"computare" which means to calculate.
Block Diagram of a Computer
Characteristics of Computer System
,Speed
A computer works with much higher speed and accuracy compared to humans while performing
mathematical calculations. Computers can process millions (1,000,000) of instructions per second.
The time taken by computers for their operations is microseconds and nanoseconds.
Accuracy
Computers perform calculations with 100% accuracy. Errors may occur due to data inconsistency or
inaccuracy.
Diligence
A computer can perform millions of tasks or calculations with the same consistency and accuracy. It
doesn’t feel any fatigue or lack of concentration. Its memory also makes it superior to that of human
beings.
Versatility
Versatility refers to the capability of a computer to perform different kinds of works with same
accuracy and efficiency.
Reliability
A computer is reliable as it gives consistent result for similar set of data i.e., if we give same set of
input any number of times, we will get the same result.
Automation
Computer performs all the tasks automatically i.e. it performs tasks without manual intervention.
Memory
A computer has built-in memory called primary memory where it stores data. Secondary storage are
removable devices such as CDs, pen drives, etc., which are also used to store data.
Basic Applications of Computer
Computers play a role in every field of life. They are used in homes, business, educational
institutions, research organizations, medical field, government offices, entertainment, etc.
Home
Computers are used at homes for several purposes like online bill payment, watching movies or
shows at home, home tutoring, social media access, playing games, internet access, etc. They
provide communication through electronic mail. They help to avail work from home facility for
corporate employees. Computers help the student community to avail online educational support.
Medical Field
Computers are used in hospitals to maintain a database of patients’ history, diagnosis, X-rays, live
monitoring of patients, etc. Surgeons nowadays use robotic surgical devices to perform delicate
operations, and conduct surgeries remotely. Virtual reality technologies are also used for training
purposes. It also helps to monitor the fetus inside the mother’s womb.
,Entertainment
Computers help to watch movies online, play games online; act as a virtual entertainer in playing
games, listening to music, etc. MIDI instruments greatly help people in the entertainment industry in
recording music with artificial instruments. Videos can be fed from computers to full screen
televisions. Photo editors are available with fabulous features.
Industry
Computers are used to perform several tasks in industries like managing inventory, designing
purpose, creating virtual sample products, interior designing, video conferencing, etc. Online
marketing has seen a great revolution in its ability to sell various products to inaccessible corners like
interior or rural areas. Stock markets have seen phenomenal participation from different levels of
people through the use of computers.
Education
Computers are used in education sector through online classes, online examinations, referring e-
books, online tutoring, etc. They help in increased use of audio-visual aids in the education field.
Government
In government sectors, computers are used in data processing, maintaining a database of citizens
and supporting a paperless environment. The country’s defense organizations have greatly
benefitted from computers in their use for missile development, satellites, rocket launches, etc.
Banking
In the banking sector, computers are used to store details of customers and conduct transactions,
such as withdrawal and deposit of money through ATMs. Banks have reduced manual errors and
expenses to a great extent through extensive use of computers.
Business
Nowadays, computers are totally integrated into business. The main objective of business is
transaction processing, which involves transactions with suppliers, employees or customers.
Computers can make these transactions easy and accurate. People can analyze investments, sales,
expenses, markets and other aspects of business using computers.
Training
Many organizations use computer-based training to train their employees, to save money and
improve performance. Video conferencing through computers allows saving of time and travelling
costs by being able to connect people in various locations.
Arts
Computers are extensively used in dance, photography, arts and culture. The fluid movement of
dance can be shown live via animation. Photos can be digitized using computers.
Science and Engineering
Computers with high performance are used to stimulate dynamic process in Science and
Engineering. Supercomputers have numerous applications in area of Research and Development
(R&D). Topographic images can be created through computers. Scientists use computers to plot and
analyze data to have a better understanding of earthquakes.
, Components of computer:
Input Unit
This unit contains devices with the help of which we enter data into the computer. This unit creates
a link between the user and the computer. The input devices translate the information into a form
understandable by the computer.
CPU (Central Processing Unit)
CPU is considered as the brain of the computer. CPU performs all types of data processing
operations. It stores data, intermediate results, and instructions (program). It controls the operation
of all parts of the computer.
CPU itself has the following three components −
• ALU (Arithmetic Logic Unit)
• Memory Unit
• Control Unit
Output Unit
The output unit consists of devices with the help of which we get the information from the
computer. This unit is a link between the computer and the users. Output devices translate the
computer's output into a form understandable by the users.
Input Devices
Keyboard
Keyboard is the most common and very popular input device which helps to input data to the
computer. The layout of the keyboard is like that of traditional typewriter, although there are some
additional keys provided for performing additional functions.
Keyboards are of two sizes 84 keys or 101/102 keys, but now keyboards with 104 keys or 108 keys
are also available for Windows and Internet.
Types of Keys
•Numeric Keys: It is used to enter numeric data or move the cursor. It usually consists of a set of 17
keys.
A computer is a programmable electronic device that accepts raw data as input and processes it with
a set of instructions (a program) to produce the result as output. It renders output just after
performing mathematical and logical operations and can save the output for future use. It can process
numerical as well as non-numerical calculations. The term "computer" is derived from the Latin word
"computare" which means to calculate.
Block Diagram of a Computer
Characteristics of Computer System
,Speed
A computer works with much higher speed and accuracy compared to humans while performing
mathematical calculations. Computers can process millions (1,000,000) of instructions per second.
The time taken by computers for their operations is microseconds and nanoseconds.
Accuracy
Computers perform calculations with 100% accuracy. Errors may occur due to data inconsistency or
inaccuracy.
Diligence
A computer can perform millions of tasks or calculations with the same consistency and accuracy. It
doesn’t feel any fatigue or lack of concentration. Its memory also makes it superior to that of human
beings.
Versatility
Versatility refers to the capability of a computer to perform different kinds of works with same
accuracy and efficiency.
Reliability
A computer is reliable as it gives consistent result for similar set of data i.e., if we give same set of
input any number of times, we will get the same result.
Automation
Computer performs all the tasks automatically i.e. it performs tasks without manual intervention.
Memory
A computer has built-in memory called primary memory where it stores data. Secondary storage are
removable devices such as CDs, pen drives, etc., which are also used to store data.
Basic Applications of Computer
Computers play a role in every field of life. They are used in homes, business, educational
institutions, research organizations, medical field, government offices, entertainment, etc.
Home
Computers are used at homes for several purposes like online bill payment, watching movies or
shows at home, home tutoring, social media access, playing games, internet access, etc. They
provide communication through electronic mail. They help to avail work from home facility for
corporate employees. Computers help the student community to avail online educational support.
Medical Field
Computers are used in hospitals to maintain a database of patients’ history, diagnosis, X-rays, live
monitoring of patients, etc. Surgeons nowadays use robotic surgical devices to perform delicate
operations, and conduct surgeries remotely. Virtual reality technologies are also used for training
purposes. It also helps to monitor the fetus inside the mother’s womb.
,Entertainment
Computers help to watch movies online, play games online; act as a virtual entertainer in playing
games, listening to music, etc. MIDI instruments greatly help people in the entertainment industry in
recording music with artificial instruments. Videos can be fed from computers to full screen
televisions. Photo editors are available with fabulous features.
Industry
Computers are used to perform several tasks in industries like managing inventory, designing
purpose, creating virtual sample products, interior designing, video conferencing, etc. Online
marketing has seen a great revolution in its ability to sell various products to inaccessible corners like
interior or rural areas. Stock markets have seen phenomenal participation from different levels of
people through the use of computers.
Education
Computers are used in education sector through online classes, online examinations, referring e-
books, online tutoring, etc. They help in increased use of audio-visual aids in the education field.
Government
In government sectors, computers are used in data processing, maintaining a database of citizens
and supporting a paperless environment. The country’s defense organizations have greatly
benefitted from computers in their use for missile development, satellites, rocket launches, etc.
Banking
In the banking sector, computers are used to store details of customers and conduct transactions,
such as withdrawal and deposit of money through ATMs. Banks have reduced manual errors and
expenses to a great extent through extensive use of computers.
Business
Nowadays, computers are totally integrated into business. The main objective of business is
transaction processing, which involves transactions with suppliers, employees or customers.
Computers can make these transactions easy and accurate. People can analyze investments, sales,
expenses, markets and other aspects of business using computers.
Training
Many organizations use computer-based training to train their employees, to save money and
improve performance. Video conferencing through computers allows saving of time and travelling
costs by being able to connect people in various locations.
Arts
Computers are extensively used in dance, photography, arts and culture. The fluid movement of
dance can be shown live via animation. Photos can be digitized using computers.
Science and Engineering
Computers with high performance are used to stimulate dynamic process in Science and
Engineering. Supercomputers have numerous applications in area of Research and Development
(R&D). Topographic images can be created through computers. Scientists use computers to plot and
analyze data to have a better understanding of earthquakes.
, Components of computer:
Input Unit
This unit contains devices with the help of which we enter data into the computer. This unit creates
a link between the user and the computer. The input devices translate the information into a form
understandable by the computer.
CPU (Central Processing Unit)
CPU is considered as the brain of the computer. CPU performs all types of data processing
operations. It stores data, intermediate results, and instructions (program). It controls the operation
of all parts of the computer.
CPU itself has the following three components −
• ALU (Arithmetic Logic Unit)
• Memory Unit
• Control Unit
Output Unit
The output unit consists of devices with the help of which we get the information from the
computer. This unit is a link between the computer and the users. Output devices translate the
computer's output into a form understandable by the users.
Input Devices
Keyboard
Keyboard is the most common and very popular input device which helps to input data to the
computer. The layout of the keyboard is like that of traditional typewriter, although there are some
additional keys provided for performing additional functions.
Keyboards are of two sizes 84 keys or 101/102 keys, but now keyboards with 104 keys or 108 keys
are also available for Windows and Internet.
Types of Keys
•Numeric Keys: It is used to enter numeric data or move the cursor. It usually consists of a set of 17
keys.
