Basics Of Computers for Beginners

2. Overview
 What is a Computer?
 Evolution of Computer
 Generations of Computer
 Classification of Computer
 Block Diagram of Computer

4. P
R
O
C
E
S
S
O
R
Input Data Output Data
Alphanume
ric
Alphanume
ric
Binary
Digits

5. Evolution Of Computer
ERA
Mechanical Electrical
ABACU
S
Blaise
Pascal
Calculato
r
Electric
Motor
Calculatin
g
Computer
500
BC
1642
1941
Konard
Zuse
1889
Herman
Hollerith

6. Generations of Computer

7. Classification of Computer
Super
Computer
Main
Frame
Computer
Mini
Computer
Micro
Comput
er
Desktop
Compute
r
Laptop
Palmtop/
PDA/
Digital
Notes

8. PERIPHERALS

9. BASIC BLOCK DIAGRAM

10. © Oxford University Press 2013. All rights reserved.
Differences

11. CPUMost of the processing takes place in CPU. During
processing, it locates and executes the program
instructions.
It also fetches data from memory and input/output
devices and sends data back.
Registers
Control
Unit
ALU

13. HardwareHardware is the physical components of a computer
that includes all mechanical, electrical, electronic and
magnetic parts attached to it.
Input and Output
Devices
CPU
Memory Storage
Devices
Interface Unit
Mouse
JoyStic
k
Touchpa
d
Webca
m
Scanne
r
Monito
r
Printe
r
Projector
s
LCD
Panels
Speaker
s

15. OUTPUT DEVICES
VDU
Printer
Plotters
Speakers
Speech Synthesizer

16. SOFTWARE
 Set of machine-readable instructions that directs a
computer's processor to perform specific operations.
Software
System EmbeddedApplication
Computer
to
operate
Uses
compute
r to
perform
Control
Machine
s or
devices

17. SOFTWARE COMPONENTS
APPLICATION
SOFTWARE
Database
Desktop
Publication
Word
Processing Spreadsheets
Payroll
Presentation
tools
Multimedia
Applications

18. Memory

19. The memory unit is composed of an ordered
sequence of storage cells, each capable of storing
one byte of data.
Primary Memory
Secondary Memory

21. PRIMARY MEMORY
Primary memory is considered as a main memory
that is accessed directly by the computer,
so as to store and retrieve.
loses all its data when the power
is turned off.
Two Technologies: RAM and ROM
Much Faster
and costlier than Secondary memory

22. RAM
Every computer comes with a certain amount of physical
memory which is actually chips that hold data.
part of hardware that stores operating system’s application
programs and currently running processes that can be
accessed randomly, i.e. in any order that the user desires.
Data in RAM stays for only as long as the computer is
running, and gets deleted as soon as computer is switched
off.
RAM usually comes in the form of microchips of different
sizes such as 256MB, 512MB, 1GB, 2GB etc.

23. ROM
Every computer comes fitted with this memory that
holds instructions for starting up the computer.
 data written permanently on it and is not reusable.
These are generally in the form of CD-ROM or Floppy
Disk that can load the OS to the RAM.

24. SECONDARY MEMORY
Secondary memory is not directly accessed through CPU .
The secondary memory is accessible in the form of Mass
storage devices such as hard disk, memory chips, Pen
drive, floppy disk storage media, CD and DVD.
The information can be retrieved even if the power is
turned off because the data will not be destructed until
and unless the user erases it.

25. STORAGE DEVICES
Hard disk drivers
Internal high capacity drivers
Stores Operating System
High Speed,Faster
Capacity-40/80GB

26. Floppy Disk
Small Disks
Portable
Very Slow
Capacity 1.44MB
CD ROM
Capacity-650MB and more…
DVD Drives
Capacity-17GB
Faster than CD not than HDD

27. Impact on Computer Performance
CPU Speed
RAM size
Hard Disk Drive Capacity

28. INTERFACE UNIT
The interface unit interconnects the CPU with
memory and also with the various input/output
(I/O) devices.
It is a set of parallel wires or lines which connects all the
internal computer components to the CPU and main
memory.

29. Depending on the type of data transmitted, a bus can
be classified into the following three types:
 Data bus : The bus used to carry actual data.
 Address bus memory or Input/output device :
Addresses travel via the address bus.
 Control bus: This bus carries control information
between the CPU and other devices within the
computer.

30. BUS BASED MEMORY
ORGANIZATION

31. MOTHER BOARD

32. MICROSOFT EXCEL

33. MEN
U BAR
TOOL
BAR
RIBBO
N
FORMULA
BAR
WOR
KSHE
ET
CELL

34. NUMBER SYSTEM
BINARY HEXADECIMAL
DECIMAL
One digit in hex corresponds to four binary digits (bits), so the
internal representation of one byte can be represented
either by eight binary digits or two hexadecimal digits.
Less commonly used is the octal (base 8) number system,
where one digit in octal corresponds to three binary digits
(bits).

35. POSITIONAL NUMBER SYSTEM
The actual number of symbols used in a positional
number system depends on its base (also called the
radix).
The highest numerical symbol always has a value of
one less than the base.
The decimal number system has a base of 10, so the
numeral with the highest value is 9; the octal number
system has a base of 8, so the numeral with the
highest value is 7, the binary number system has a
base of 2, so the numeral with the highest value is
1, etc.

36. DECIMAL SYSTEM
1 2 7 510
5 x 100 = 5 x 1 = 5
7 x 101 = 7 x 10 = 70
2 x 102 = 2 x 100 = 200
1 x 103 = 1 x 1000 = 1000
------
1275 10
Each position represents a specific power of base 10.
=1
0
10
3
10
0
n
1
10
0
n

37. TRY THIS: Expand the following decimal number:
5 1 3 010

38. BINARY SYSTEM
Each position of the binary number represents a
successive power of two.
Decimal Binary Decimal Binary
0 0 16 10000
1 1 17 10001
2 10 18 10010
3 11 19 10011
4 100 20 10100
5 101 21 10101
6 110 22 10110
7 111 23 10111
8 1000 24 11000
9 1001 25 11001
10 1010 26 11010
11 1011 27 11011
12 1100 28 11100
13 1101 29 11101
14 1110 30 11110
15 1111 31 11111

39. BINARY to DECIMAL
To determine the value of a binary number (10012, for
example), we can expand the number using the
positional weights as follows:
1 0 0 12
1 x = 1 x 1 = 1
0 x = 0 x 2 = 0
0 x = 0 x 4 = 0
1 x = 1 x 8 = 8
------
9 10
0
2
1
2
2
2
3
2

40. TRY THIS: Convert the following binary numbers
to their decimal equivalents:
(a) 1 1 0 0 1 1 02

41. DECIMAL to BINARY
Remainder Method
(1) Divide the decimal number by the base (in the
case of binary, divide by 2).
(2) Indicate the remainder to the right.
(3) Continue dividing into each quotient (and
indicating the remainder) until the divide operation
produces a zero quotient.
(4) The base 2 number is the numeric remainder
reading from the last division to the first (if you start
at the bottom, the answer will read from top to
bottom).

42. TRY THIS: Convert the following decimal
numbers to their binary equivalents:
(a) 4910 (b) 2110

43. BINARY ADDITION
Adding two binary numbers together is easy, keeping
in mind the following four addition rules:
(1) 0 + 0 = 0
(2) 0 + 1 = 1
(3) 1 + 0 = 1
(4) 1 + 1 = 10

44. BINARY SUBTRACTION
11010101 - 1001011
(1) Compute the one's complement of 10010112 by
subtracting each digit from 1 (note that a leading
zero was added to the 7-
digit subtrahend to make it the same size as the 8-digit
minuend):
1 1 1 1 1 1 1 1
- 0 - 1 - 0 - 0 - 1 - 0 - 1 - 1
1 0 1 1 0 1 0 0
2
2 2
MINUEND - SUBTRAHEND = DIFFERENCE

45. (2) Add 1 to the one's complement of the subtrahend,
giving the two's complement of the subtrahend:
1 0 1 1 0 1 0 0
+ 1
1 0 1 1 0 1 0 1
(3) Add the two's complement of the subtrahend to the
minuend and drop the high-order 1, giving the
difference:
1 1 1 1 1
1 1 0 1 0 1 0 1
+ 1 0 1 1 0 1 0 1

46. OCTAL NUMBER SYSTEM
The base of the octal number system is eight, so each
position of the octal number represents a successive
power of eight. From right to left, the successive
positions of the octal number are weighted 1, 8, 64,
512, etc. A list of the first
several powers of 8 follows:
80= 1 = 8 = 64 83= 512 …84 = 4096 85 = 32768
18
18
28

47. OCTAL to DECIMAL
3 6 78
7 x 80 = 7 x 1 = 7
6 x 81 = 6 x 8 = 48
3 x 82 = 3 x 64 = 192
------
247 10

48. TRY THIS: Convert the following octal numbers
to their decimal equivalents:
(a) 5 3 68

49. DECIMAL to OCTAL
(1) Divide the decimal number by the base (in the case
of octal, divide by 8).
(2) Indicate the remainder to the right.
(3) Continue dividing into each quotient (and
indicating the remainder) until the divide operation
produces a zero quotient.
(4) The base 8 number is the numeric remainder
reading from the last division to the first (if you start
at the bottom, the answer will read from top to
bottom).

50. HEXADECIMAL SYSTEM
The hexadecimal number system uses not only the
Arabic numerals 0 through 9, but also uses the letters
A, B, C, D, E, and F to represent the equivalent of 1010
through 1510, respectively.

51. HEXADECIMAL to DECIMAL
How to convert from hex to decimal
A regular decimal number is the sum of the digits
multiplied with its power of 10.
Example #1
137 in base 10 is equal to each digit multiplied with its
corresponding power of 10:
13710 = 1×102
+3×101
+7×100
= 100+30+7

52. COMPUTER CHARACTER SET
AND DATA REPRESENTATION
ASCII (pronounced "as-key", stands for American
Standard Code for Information Interchange) is
(used on most minicomputers and PCs)
32 through 127 of the ASCII character set, which
encompass (letters, numbers, and special characters).
0-31---->Control Characters(modems, printers, and
keyboards work)Eg:Printers character 12 for “form
feed”
128-255Box Drawing Characters Eg:Making dialog
box,non-GUI..

53. EBCDIC (pronounced "eb-suh-dick", stands for
Extended Binary Coded Decimal Interchange
Code)
(used on IBM mainframes)

54. FLOW CHART
A flow chart is a graphical or symbolic representation
of a process.
Each step in the process is represented by a different
symbol and contains a short description of the
process step.
The flow chart symbols are linked together with
arrows showing the process flow direction.