UGC NET Paper 1 ICT Memory and data

1. UGC NET- ICT
MEMORY AND DATA
Megha V
Research Scholar
Kannur University

2. MEMORY STRUCTURE
Bit (Binary Digit) – A binary digit is logical 0 and 1
Nibble- A group of 4 bits
Byte – A group of 8 bits
Word - A group of fixed number of bits processed as a unit
- varies from computer to computer
By grouping bits together we can store more values
• 8 bits = 1 byte
• 16 bits = 2 bytes = 1 halfword
• 32 bits = 4 bytes = 1 word

3. LARGER UNITS OF INFORMATION STORAGE
• 1 Kilobyte (KB) = 210 bytes = 1,024 bytes
• 1 MegabByte (MB) = 1,024 KB = 220 bytes = 1 Million bytes
• 1 Gigabyte (GB) = 1,024 MB = 230 bytes = 1 Billion bytes
• 1 Terabyte(TB)=1024 GB =240 bytes = 1 Trillion bytes
• 1 Petabyte (PB)=1024 TB = 250 bytes = 1 quadrillion bytes
• 1 Exabyte(EB) =1024 PB= 260 bytes = 1 quintillion bytes
• 1 Zettabyte (ZB) = 1024 EB = 270 bytes = 1 sextillion bytes
• 1 Yottabyte (YB) = 1024 ZB= 280 bytes = 1 septillion bytes

4. NUMBER SYSTEM
Decimal (base-10) number system
• We have symbols (digits) that can represent ten integer values: 0, 1, 2, 3, 4, 5, 6, 7, 8,
9
• We represent integer values larger than 9 with combinations of two or more digits,
e.g.: 10, 11, 12, ..., 112, ..., 247
e.g.: 247
= (7 x 100 ) + (4 x 101 ) + (2 x 102 )
2 is the Most Significant Digit
7 is the Least Significant Digit

5. NUMBER SYSTEM
Binary (Base 2) Number system
• Computer systems store information electronically using bits (binary digits)
• Each bit can be in one of two states, which we can take to represent the binary (base-2)
digits 0 and 1
• The binary number system is a natural number system for computing (rather than the
decimal system)
• Using a single bit, we can represent integer values 0 and 1
• Using two bits, we can represent 0, 1, 10, 11

6. NUMBER CONVERSION
• Binary to Decimal Conversion
100101 = (1 x 20 ) +
(0 x 21 ) + LSB - Least Significant Bit
MSB LSB (1 x 22 ) + MSB – Most Significant Bit
(0 x 23 ) +
(0 x 24 ) +
(1 x 25 ) +
= 37 (100101)2 = (37)10

7. • Binary fraction to Decimal Conversion
NUMBER CONVERSION
11001.11
decimal part 11001= fractional part .11 =
( 1 x 20 ) = 1+ (1 x 2 -1 ) + = 0.50 +
( 0 x 21 ) = 0+ (1 x 2 -2 ) = 0.25
( 0 x 22 ) = 0 +
( 1x 23 ) = 8 + = .75
( 1 x 24 ) = 16
= 25
(11001.11)2 = (25.75)10

8. NUMBER CONVERSION
• Decimal to Binary Conversion
Convert 37 to its binary equivalent?
Quotient Remainder Binary digit
37 / 2 = 18 1 1
18 / 2 = 9 0 0
9 / 2 = 4 1 1
4 / 2 = 2 0 0
2 / 2 = 1 0 0
1 / 2 = 0 1 1 (37)10 = (100101)2

9. NUMBER CONVERSION
• Decimal fraction to Binary Conversion
Convert 25.75 to its binary equivalent?
Decimal Part 25 Fractional Part 0.75
Quotient Remainder Binary digit
25 / 2 = 12 1 1 0.75 x 2 = 1.50 1
12 / 2 = 6 0 0
6 / 2 = 3 0 0 0.50 x 2 = 1.0 1
3 / 2 = 1 1 1
1 / 2 = 0 1 1
(25.75)10 = (11001.11)2