2. What is a Computer?
• A computer is an electronic device that accepts data
from the user, processes it, produces results, displays
them to the users, and stores the results for future
usage.
• Data is a collection of unorganized facts & figures and
does not provide any further information regarding
patterns, context, etc. Hence data means "unstructured
facts and figures".
• Information is a structured data i.e. organized
meaningful and processed data. To process the data
and convert into information, a computer is used.
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4. 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.
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5. Accuracy
• Computers perform calculations with 100%
accuracy. Errors may occur due to data
inconsistency or inaccuracy.
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6. 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.
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7. Versatility
• Versatility refers to the capability of a
computer to perform different kinds of works
with same accuracy and efficiency.
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8. 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.
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9. Automation
• Computer performs all the tasks automatically
i.e. it performs tasks without manual
intervention.
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10. 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.
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11. Components of Computer
• Computer systems consist of three components as shown in below image:
– Central Processing Unit,
– Input devices and
– Output devices.
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13. Organization of Computer
• Computer organization consist of following
parts
• CPU – central processing unit
• Memory
• Input devices
• Output devices
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14. Input Devices
• A device that can be used to insert data into a computer system is called
as input device. It allows people to supply information to computers.
• An input device is any hardware device that sends data to the computer,
without any input devices, a computer would only be a display device and
not allow users to interact with it, much like a TV.
• The most fundamental pieces of information are keystrokes on
a keyboard and clicks with a mouse. These two input devices are essential
for you to interact with your computer. Input devices represent one type
of computer peripheral.
• Examples of input devices include keyboards, mouse, scanners, digital
cameras and joysticks.
• Input devices provide data input to processor, which processes data and
generates useful information that’s displayed to the user through output
devices. This is stored in computer’s memory.
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15. CPU – central processing unit
• It is alternatively referred to as the brain of the
computer, processor, central processor, or microprocessor,
the CPU was first developed at Intel with the help of Ted Hoff
in the early 1970’s and is short for Central Processing Unit.
The computer CPU is responsible for handling all instructions
it receives from hardware and software running on the
computer.
• 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 computer.
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17. • CPU itself has following three components
• ALU (Arithmetic Logic Unit)
• Memory Unit
• Control Unit
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18. Arithmetic Logic Unit (ALU)
• All arithmetic calculations and logical
operation are performed using the
Arithmetic/Logical Unit or ALU
• Data entered into computer is sent to RAM, from
where it is then sent to ALU, where rest of data
processing takes place. All types of processing,
such as comparisons, decision-making and
processing of non-numeric information takes
place here and once again data is moved to RAM.
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19. Control Unit
• As name indicates, this part of CPU extracts instructions,
performs execution, maintains and directs operations of
entire system.
• Control unit help to perform operations of input unit,
output unit, Memory unit and ALU in a sequence.
• Functions of Control Unit
– It controls all activities of computer
– Supervises flow of data within CPU
– Directs flow of data within CPU
– Transfers data to Arithmetic and Logic Unit
– Transfers results to memory
– Fetches results from memory to output devices
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20. Memory
• A memory is just like a human brain. It is used to store data and
instruction. Computer memory is use to Stores information being processed
by the CPU
• Computer memory is any physical device capable of storing information
temporarily or permanently. For example, Random Access Memory RAM is a
type of volatile memory that is stores information on an integrated circuit, and
that is used by the operating system, software, hardware, or the user.
• This is unit in which data and instructions given to computer as well as results
given by computer are stored. Unit of memory is "Byte".
• 1 Byte = 8 Bits
• Computer memory divide into two parts
• 1.Volatile memory
• Volatile memory is a temporary memory that loses its contents when the
computer or hardware device loses power.eg. RAM
• 2.Non-volatile memory
• Non-volatile memory keeps its contents even if the power is lost. Example:
ROM or EPROM is a good example of a non-volatile memory
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21. Output Devices
• A device which is used to display result from a computer is
called as output device. It Allows people to receive
information from computers.
• An output device is any peripheral that receives or displays
output from a computer. The picture shows an inkjet printer,
an output device that can make a hard copy of anything being
displayed on a monitor.
• Output device is electronic equipment connected to a
computer and used to transfer data out of the computer in
the form of text, images, sounds or print.
• Examples of output devices include Printer, Monitor, etc.
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