A computer is an electronic device that takes input, processes it, and provides output. It uses binary digits (0s and 1s) and stores data for further processing. The main components of a computer are the central processing unit (CPU), memory, storage, input devices, and output devices. The CPU contains the control unit and arithmetic logic unit (ALU) and works with the operating system and other programs to process data. Memory (RAM and ROM) is used to store programs and data temporarily or permanently. Common input devices include keyboards, mice, and scanners. Common output devices include monitors, printers, and speakers.

2. What is a computer ?
• A Computer is an electronic device which takes input through input devices,
processes it and gives the output through output devices.
• It also stores data for further processing.
• Computer works with 0’s & 1’s(Binary).
• Like all electronic devices a computer works with DC power supply.

3. Block diagram of a computer
ALU
Control
Unit
Memory
Input Unit
Output
unit

4. Types of computers

6. What is computer hardware?
• Computer hardware is the collection of physical parts of a computer system
• Computer hardware is what you can physically touch.
• This includes the computer case, monitor, keyboard, and mouse. It also
includes all the parts inside the computer case, such as the hard disk drive,
motherboard, video card, and many others

7. Components of a computer
• Motherboard
• Processor
• Primary Storage Devices
• RAM (Random Access Memory)
• ROM (Read Only Memory)
• Secondary Storage Devices
• HDD (Hard Disk Drive)
• Optical Drives (CDROM, DVD, etc)
• Floppy Disk drive
• SMPS (Switched Mode Power Supply)
• Input Devices
• Keyboard
• Mouse
• Output Devices
• Monitor
• Printer

9. Processors
• It is the brain of the computer
• It is a semi-conductor device
• It contains the complete CPU (Central Processing Unit) in a single chip
• It performs Arithmetic and logical functions

10. Processor Specifications
• Speed (measured in Hz (Hertz))
• Width (measured in bits, Ex: 16bits,32bits or 64bits)
• FSB Speed (Front Side Bus) (measured in Hz)
• Cache memory (measured in Kbytes/Mbytes)

11. Types of processors
Slot type processor
Socket type processor

12. Processor Manufacturers
• Intel
• AMD(Advanced Micro Devices)
• VIA
• Motorola

13. Generation of the processors
• First Generation(4004, 8008, 8080, 8086, 80186)
• Second generation(80286)
• Third generation (80386)
• Fourth generation (80486)
• Fifth generation (Intel Pentium & AMD K5)
• Sixth generation (Intel Pentium I I & AMD K6)
• Seventh generation (Intel Pentium III , AMD Athlon & Cyrix III)
• Eighth generation (Intel Pentium IV & AMD AthlonXp)
• Ninth generation (Intel Pentium Extreme Edition & AMD Athlonfx
64bit)

14. Intel Pentium processors
PENTIUM PROCESSOR PENTIUM – II PROCESSOR

15. Primary Storage Classification
PRIMARY STORAGE
ROM
RAM
Static RAM Dynamic RAM

16. RAM(Random Access Memory)
• Primary storage for the CPU.
• Integrated circuits (chips) are used to temporarily store programs,
instructions and data.
• It is a volatile memory (requires power to store the data).

17. Static Ram (Cache Memory)
• The CPU process data at a very high speed.
• Dynamic RAM cannot match that speed.
• Hence, a special type of RAM called as cache is used.
• Cache memory stores instructions and data which the CPU is currently
working on or may soon need.
• Cache levels:
• The cache memory that is placed inside the actual CPU is called level l cache (internal
cache memory).
• The cache memory located on the die of the CPU is called as level ll cache (external
cache memory).

18. Cache Location

19. Types of Dynamic-Ram
SD-RAM(Synchronous dynamic)
168 pins.
DDR-RAMS(Double data rate)
184 pins.
DDR2-RAMS(Double data rate)
240 pins
DDR3-RAMS(Double data rate)
240 pins.

20. ROM(Read Only Memory)
–Integrated circuits that are used to permanently store start-up (boot)
instructions and other critical information.
• Types of ROM:
-PROM(Programmable Read Only Memory)
-EPROM(Erasable Programmable Read Only Memory)
-EEPROM (Electrically Erasable Programmable Read Only Memory)

21. BIOS (Basic input output system)
• During the boot up it performs POST(Power On Self Test)
• Recognizes the hardware devices
• Locates and loads the operating system
• It helps the operating system to access the hardware devices
Bios chip

23. Components on the motherboard
• Processor slot/socket
• Memory Slots
• Expansion Slots
• I/O Ports
• Chipsets
• IDE / SATA Connectors
• Floppy Drive Connector
• CMOS Battery
• Power Supply connector
• Heat Sink
• Front Panel Connectors

24. Motherboard

25. Input / Output (I/O) PORTS
MOUSE
KEYBOARD
SERIAL PORT
VGA PORT
AUDIO PORTS
RJ-45
USB PORTS

26. CMOS Battery
• CMOS(Complementary Metal Oxide Semiconductor) RAM is used to
store the date, time, and system configuration
• Battery which powers this memory is called as CMOS Battery

28. Secondary Storage Devices
• Magnetic storage devices
- Harddisk
- Floppy disk
- Tape drive
- Zip drive
• Optical storage devices
• Compact Disc(CD)
• Digital Versatile Disc(DVD)
• Blu Ray Disc(BRD)

29. Hard Disk
• Uses magnetic media for storing data
• Non-volatile permanent storage device
• Mass storage devices
• Interfaces used
• IDE / EIDE (Enhanced IDE)
• SATA

30. IDE Hard-disk Connectors

31. SATA Hard Disk Connectors

32. Tracks and Cylinders

33. Sectors
• Sector is a section of a track which stores a predetermined number of bytes

34. Measure hard disk size
• Bit :Â A Bit is a value of either a 0 or 1.
• Byte : 1 Byte = 8 Bits
• 1 Kilobyte (kB) = 1,024 Bytes
• Megabyte (MB) 1MB =1024 KB
• Gigabyte (GB) 1GB = 1024 MB
• Terabyte (TB) 1TB = 1024 GB
• Petabyte (PB) 1PB = 1024 TB
• Exabyte (EB) 1EB = 1024 PB
• Zettabyte (ZB) 1ZB = 1024 EB

35. Storing Data on a Hard-Disk
• Bits are recorded as positive and negative polarity on magnetic
media

36. CDROM/Combo/DVD

37. Optical Drive Back Panel

38. CD/DVD Surface
• In CD or DVD data is stored in the form of lands and pits
• Land can reflect laser beam and pit will absorb the laser beam
• While reading data if the light emitted by laser is reflected then it is
treated as binary ‘1’ and if laser beam is not reflected then it is treated
as binary ‘0’
Pit
Land

39. INPUT DEVICE
An input device is a piece of computer hardware
equipment used to provide data and control signals to an
information processing system such as computer or
information appliance.

40. Major input devices :-
Some of the major input devices are:-
 KEYBOARD
 MOUSE
 JOYSTICK
 OMR( OPTICAL MARK READER)
 LIGHT PEN
 POINT OF SCALE TERMINAL(POS TERMINAL)
 BCR( BAR CODE READER)
 OCR (OPTICAL CHARACTER READER)
 MICR( MAGNETIC INK CHARACTER READER)

41. Keyboard is a flat piece of plastic board many buttons
arranged on it . These buttons are called keys. The
keyboard help in inputting the data to the computer .
There are following functions keys on a keyboard like
F1 to F12 , numeric keys 0 to 9 and alphabet keys A to
Z . It consists caps lock key, num lock key ,shift key
,back space key ,space bar key and enter key etc.
Standard keys on a keyboard is 101.
KEYBOARD:-

42. MOUSE :-
Mouse is a pointing device it consist three buttons. Left button
right button and scroll button . Left button is used to select an
object , right button is used to excess the properties of an object
and scroll button is used to scrolling the page up and down.
Mouse are basically used in desktop computer system when
placed on a fixed space than we use mouse.

43. JOYSTICK:-
Joystick is a pointing device most common used to play
animated games on a micro computer. Joystick works on
the same principal as a trackball. Joysticks are often used
to control video games and usually have one or more
push buttons whose state can also be read by the
computer.

44. OPTICAL MARK READER:-
Optical mark reader is a special optical scanner device which can
be used to recognise the type of mark made by pencil or pen. This
device is used as academic and examination centres to grade
aptitude test. Where candidate mark the correct answers on a
special sheet of paper having multiple circles. These answer
sheets are the directly read by the optical mark reader and the
corresponding information is sent to a CPU for processing.

45. LIGHT PEN:
Light pen is a pointing device that can be a used to choose a
displayed menu option or to draw picture on the screen. It
consist of a photocell and an optical system placed in a small tube
as the user moves tip on the pen over the surface. It is able to
detect the light coming from a limited field of view. A light pen is
also useful for graphic , the user at computer added design
terminal can draw directly on the screen with the pen.

46. POINT OF SCALE TERMINAL (POS
TERMINAL ):-
It is a higher version of the bar code reader , also used in
departmental stores. In this case, the salesman move about,
carrying with them a barcode reader and a laptop computer.
When a customer wants to purchase something, the salesman
with the aid of the barcode reader and the laptop computer,
decodes the detailed information in printed on the barcode of
that product.

47. BCR (BAR CODE READER):-
Various commodities available in the market have a sequence of
black and white lines of varying thickness, closely placed together
printed on the cover . These lines which are known as barcodes .
Barcodes contains the various information about the product, e.g.
name of the product, manufacturing date, producer name, expiry
date, cost of production etc.

48. OCR(OPTICAL CHARACTER
READER):-
Optical character reader is a optical scanner used to scan
documents place under them by examining each character present
in the document and matching it the character may be either typed
or hand return. In case of hand return characters special care has to
be taken to ensure that the characters are of standard size , line
making up the character are connected.
OCR devices are particularly used for large volume
application such as reading zip codes in postal service and printing
bill of credit card.

49. MICR(MAGNETIC INK
CHARACTER READER:-
It is popularly used in banks for verifying important documents
like drafts, cheques etc. At the bottom side of such documents, a
set of symbols are printed with magnetized ink.

50. OUTPUT DEVICES:-
An output device is any device used to send data from a
computer to another device or user . Most computer data output
that is meant for humans is in the form of audio or video. They
perform the following function:-
 Receive result from memory
 Convert data into human readable form
 Display result to the user

51. DIFFERENT TYPES OF OUTPUT
DEVICE:-
MONITOR
PRINTER
IMPACT PRINTER
NON –IMPACT PRINTER
SPEAKER AND HEADSETS
PLOTTER
MULTIMEDIA PROJECTER

52. MONITOR:-
The monitor is the most common and the most important
output device. It is also called a visual display unit. The output
viewed on a monitor is called a soft copy. The monitor is a visual
display device to present output information in the form of text,
graphic, or video on the monitor screen.

53. PRINTERS:-
Printers are used to produce hard copy output. They print
processing results on paper. Printers are divided into two main
categories:-
Impact printer
Non- impact printer

54. IMPACT PRINTERS:-
The printer that print the character by striking against the
ribbon and into the paper is called impact printer. There are two
types of impact printer.
Character printer
line printer

55. CHARACTER PRINTER :-
These printer print one character at a time is called
character printer . For example Dot matrix printer.
They form character and all kind of image as pattern or
dots.

56. LINE PRINTER:-
These printer print one line at a time. So it is called as line printer.
These printer use impact technology. There is mechanical contact
between head and a paper . These are first printer having speed in
the range of 3000 lines per minutes.

57. NON – IMPACT PRINTERS:-
Non impact printer that prints the character without striking
against the ribbon and on the paper is called non impact printer.
These printer print a complete page at a time so also called page
printer . There are two types of non impact printer.
Inkjet printer
laser printer

58. INKJET PRINTER:-
These printer prints the
character by spraying the
paper with electrically
charged ink . They give better
quality than character
printer. They are cheaper
than laser printer.
LASER PRINTER:-
These are based on laser
technology with high speed
and high quality printing .In
these printer a laser beam is
used to write the image on a
paper.

59. SPEAKER AND HEADSETS:-
Speaker and head sets produce sound output. We can listen
recorded voices, sounds or music with the help of speaker or
headset. Speaker produce sound output with the help of sound
card.

60. PLOTTER:-
A plotter is an output device used to produce image quality
graphics in a variety of colors. Plotter are used to print large
maps, architectural drawings, graphs and charts. Plotter are used
o draw different design of building or internal structure of
machines. Plotters offer the fastest way to efficiently produce
very large drawing or color high resolution graphics. Engineers and
architects use plotters.

61. DRUM PLOTTER:-
In drum plotter both paper and
drum move to produce the
output. The plotter was the first
output device to print graphic
and large engineering drawings.
FLATBED PLOTTER
In this plotter the paper is fixed and drum moves. Flatbed plotters
have a large horizontal surface on which the paper is placed.

62. MULTIMEDIA PROJECTOR:-
Multimedia projector is used to produce computer output on a
big screen. These are used in meeting rooms or in classroom of
educational institutes. Since the output produced by multimedia
projector is displayed on a large screen, it can be viewed by a
large number of people in a hall, meeting /conference room or a
class room .Mostly teachers used data projector in class room for
delivering lectures.