The document discusses data representation in computers and various computer coding schemes. It provides details about Binary Coded Decimal (BCD) coding, including that it uses 6 bits to represent symbols, allowing for 64 possible codes. BCD is described as an early computer code developed by IBM that was commonly used in digital devices. The coding of alphabetic and numeric characters in BCD is shown, along with an example of encoding the word "BASE" in BCD binary digits. Advantages of BCD include ease of encoding/decoding decimals, while disadvantages include slower arithmetic operations due to complex circuitry and limited character set.

1. TUMKUR UNIVERSITY
Dept. of Library and Information Science
A SEMINAR PRESENTATION
ON
bcd
SUBMITTED BY:
MEGHANA .C.M
1ST M.Sc. Physics ,II Sem
Dept. of Studies and Research in Physics
Tumkur University, Tumkur

2. Introduction:
• Data representation refers to the internal method used to
represent various types of data stored on a computer.
Computers use different types of numeric codes to represent
various forms of data, such as text, number, graphics and sound.
• The computer has switches to represent data and switches have
only two states: ON and OFF. Binary has two digits to do the
counting: 0 and 1 (0 = OFF, 1 = ON).

3. • Computer codes are codes that help in converting the data
entered by the users into the binary form.
• Computer codes use binary coding schemes.In binary coding,
every symbol that appears in the data is represented by a group
of bits.
• The group of bits used to represent a symbol is called a byte.
• As most modern coding schemes use 8 bits to represent a
symbol, the term byte is often used to mean a group of 8 bits.

4. Commonly used computer codes:
• BCD
• EBCDIC
• ASCII
• Gray Code
• UNI Code

5. BCD
• BCD stands for Binary Coded Decimal.
• It is one of the early computer codes
• BCD system was developed by the IBM corporation.
• It uses 6 bits to represent a symbol.
• It can represent 64 ( 26 ) different characters.

6. Coding of Alphabetic Characters in BCD
Character
BCD Code
Zone Digit
A 11 0001
B 11 0010
C 11 0011
D 11 0100
E 11 0101
F 11 0110
G 11 0111
H 11 1000
I 11 1001
J 10 0001
K 10 0010
L 10 0011
M 10 0100
Character
BCD Code
Zone Digit
N 10 0101
O 10 0110
P 10 0111
Q 10 1000
R 10 1001
S 01 0010
T 01 0011
U 01 0100
V 01 0101
W 01 0110
X 01 0111
Y 01 1000
Z 01 1001

7. Coding of Numeric Characters in BCD
Character
BCD Code
Zone Digit
1 00 0001
2 00 0010
3 00 0011
4 00 0100
5 00 0101
6 00 0110
7 00 0111
8 00 1000
9 00 1001
10 00 1010

8. BCD Coding Scheme
Example:
Show the binary digits used to record the word BASE in BCD.
Solution:
B=110010 in BCD binary notation
A=110001 in BCD binary notation
S=010010 in BCD binary notation
E=110101 in BCD binary notation
So the binary digits
110010 110001 010010 110101
B A S E
will record the word BASE in BCD.

9. Advantages of BCD Code :
• It is easy to encode and decode decimals into BCD and
vice versa.
•Digital voltmeters, frequency converters and digital clocks
all use BCD as they display output information in decimal.
Binary Clock
The time 9:05:53 in BCD Mode.

10. Disadvantages of BCD Code:
•The speed of the arithmetic operations that can be
realised using BCD code is naturally slow due to
the complex hardware circuitry involved.
•Computers using BCD codes could work only with
upper case letters and 0 to 9 numbers and few
characters.

11. THANK YOU