fundamentals of computer system

1. Fundamentals of Computer
System
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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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3. Characteristics and Features of the
computer
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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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12. Block Diagram of Computer
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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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22. Input Devices
• Touch Screen
• OMR
• OBR
• OCR
• Light Pen
• Scanner
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23. Touch Screen
• A touch screen is a computer display screen
that is also an input device. The screens are
sensitive to pressure; a user interacts with the
computer by touching pictures or words on
the screen.
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24. OMR
• OMR is a special type of optical scanner used to
recognize the type of mark made by pen or pencil. It
is used where one out of a few alternatives is to be
selected and marked.
• It is specially used for checking the answer sheets of
examinations having multiple choice questions.
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25. OBR
• Bar Code Reader is a device used for reading bar coded data
(data in the form of light and dark lines). Bar coded data is
generally used in labelling goods, numbering the books, etc. It
may be a handheld scanner or may be embedded in a
stationary scanner.
• Bar Code Reader scans a bar code image, converts it into an
alphanumeric value, which is then fed to the computer that
the bar code reader is connected to.
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26. OCR
• OCR is an input device used to read a printed text.
• OCR scans the text optically, character by character,
converts them into a machine readable code, and
stores the text on the system memory.
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27. Light Pen
• Light pen is a pointing device similar to a pen. It is used to
select a displayed menu item or draw pictures on the monitor
screen. It consists of a photocell and an optical system placed
in a small tube.
• When the tip of a light pen is moved over the monitor screen
and the pen button is pressed, its photocell sensing element
detects the screen location and sends the corresponding
signal to the CPU.
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28. Scanner
• Scanner is an input device, which works more like a
photocopy machine. It is used when some information is
available on paper and it is to be transferred to the hard disk
of the computer for further manipulation.
• Scanner captures images from the source which are then
converted into a digital form that can be stored on the disk.
These images can be edited before they are printed.
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29. Digitizers
• Digitizer is an input device which converts analog information into digital
form. Digitizer can convert a signal from the television or camera into a
series of numbers that could be stored in a computer. They can be used by
the computer to create a picture of whatever the camera had been
pointed at.
• Digitizer is also known as Tablet or Graphics Tablet as it converts graphics
and pictorial data into binary inputs. A graphic tablet as digitizer is used
for fine works of drawing and image manipulation applications.
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30. Output Devices
• Plotters
• LCD Projector
• Plasma Display
• Printers
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31. Plotter
• A plotter is a computer hardware device much like a printer
that is used for printing vector graphics. Instead of
toner, plotters use a pen, pencil, marker, or another writing
tool to draw multiple, continuous lines onto paper rather than
a series of dots like a traditional printer.
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32. LCD Projector
• An LCD projector is a type of video projector for displaying video, images or
computer data on a screen or other flat surface. It is a modern equivalent of the
slide projector or overhead projector.
• They are commonly used in business meetings, presentations and seminars.
• LCD projectors work by using three liquid crystal panels, a lamp, a prism, and
filters to create the image on the screen. From there the LCD panels send the light
through the dichroic prism which recombines the light and sends it out the main
lens in the LCD projector to the surface against which it is projected.
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33. Plasma Display
• A plasma display is a computer video display in which each
pixel on the screen is illuminated by a tiny bit of plasma or
charged gas, somewhat like a tiny neon light. Plasma
displays are thinner than cathode ray tube ( CRT
) displays and brighter than liquid crystal displays ( LCD ).
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34. Printers
• Printer is an output device, which is used to print information
on paper.
• There are two types of printers −
• Impact Printers
• Non-Impact Printers
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35. • Impact Printers
– Impact printers print the characters by striking them on the ribbon,
which is then pressed on the paper.
• Characteristics of Impact Printers are the following −
– Very low consumable costs
– Very noisy
– Useful for bulk printing due to low cost
– There is physical contact with the paper to produce an image
• These printers are of two types −
• Character printers
• Line printers
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36. • Character Printers
– Character printers are the printers which print one
character at a time.
• These are further divided into two types:
– Dot Matrix Printer(DMP)
– Daisy Wheel
• Line Printers
– Line printers are the printers which print one line at a time.
• These are of two types −
– Drum Printer
– Chain Printer
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37. • Non-impact Printers
– Non-impact printers print the characters without using the ribbon. These
printers print a complete page at a time, thus they are also called as Page
Printers.
• Characteristics of Non-impact Printers
– Faster than impact printers
– They are not noisy
– High quality
– Supports many fonts and different character size
• These printers are of two types −
• Laser Printers
• Inkjet Printers
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38. Software
• Software is a set of programs, which is designed to
perform a well-defined function. A program is a
sequence of instructions written to solve a particular
problem.
• There are two types of software −
• System Software
• Application Software
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39. System Software
• The system software is a collection of programs designed to
operate, control, and extend the processing capabilities of the
computer itself. System software is generally prepared by the
computer manufacturers. 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 the hardware and the end
users.
• Some examples of system software are Operating System,
Compilers, Interpreter, Assemblers, etc.
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40. Features of a system software
• Close to the system
• Fast in speed
• Difficult to design
• Difficult to understand
• Less interactive
• Smaller in size
• Difficult to manipulate
• Generally written in low-level language
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41. Application Software
• Application software products are designed to satisfy a particular
need of a particular environment. All software applications
prepared in the computer lab can come under the category of
Application software.
• Application software may consist of a single program, such as
Microsoft's notepad for writing and editing a 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.
• Examples of Application software are the following −
• Payroll Software, Student Record Software, Inventory Management
Software, Income Tax Software, Railways Reservation Software,
Microsoft Office Suite Software, Microsoft Word, Microsoft Excel,
Microsoft PowerPoint
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42. Features of application software
• Close to the user
• Easy to design
• More interactive
• Slow in speed
• Generally written in high-level language
• Easy to understand
• Easy to manipulate and use
• Bigger in size and requires large storage space
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