Lecture Outline – Computer Number Systems
Decimal
Binary
ASCII
Hexadecimal
Bit/Byte
K
G
T
P
X
Z
Y
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0-9
Decimal Power 103 = 1,000 = 1K
Two digit number system
0-1
Binary Power 210 = 1024 = 1K
Binary Number System created by Ada Lovelace
Binary System adopted for computer use by John Atanasoff
American Standard Code for Information Interchange
8 bit code two – four bit groups of binary digits
Represents: numbers, characters, symbols, and control codes
0-127 – Standard Set
128-256 – Extended Set
Developed by ANSI (American National Standards Institute) for to support
additional alphabet, currency, etc.
Different ASCII extensions are used by different manufactures
Hex
16 digit number system
Decimal numbers 0-15 = Hex numbers 0-F
Use lower case h suffix to denote hex
Shorthand way to represent ASCII code
0100 1101 = 4Dh
Bit = b – 1 data element – 0 or 1 (bit came from = binary digit)
Byte = B = 8bits = (ASCII in binary = 2 – 4 bit groups
Binary:
0100 1101 equals:
Decimal:
4 13
Hex:
4
D
ASCII #:
77
ASCII Character:
M
Word – 2 Bytes read in reverse order
(Word - Also - Natural data size of processor - for a 32 bit processor - 1 Word = 32bits)
(Word – Also - Programming - Short Word – 2 bits, Long Word = 4 bits)
Dword – 4 Bytes read in reverse order (double word)
LoWord – First Byte of Dword
HiWord – Second Byte Dword
Kilo = Thousand – 10 to the 3rd power
1,000
Mega = Million – 10 to the 6th
In binary systems, mega stands for 2 to the 20th power, or 1,048,576.
1,000,000
9
Giga = Billion - 10
(Binary Giga represents 2 to the 30th power, which is 1,073,741,824)
1,000,000,000
Tera = Trillion - 1012
1,000,000,000,000
Peta - 1015
1,000,000,000,000,000
Exa - 1018
1,000,000,000,000,000,000
21
Zetta – 10
1,000,000,000,000,000,000,000
Yotta – 1024
1,000,000,000,000,000,000,000,000
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Richard Goldman
Lecture Outline – Computer Number Systems
m
Milli – 10-3

Micro - 10-6
n
Nano – 10-9
p
Pico - 10-12
0.001
0.000,001
0.000,000,001
0.000,000,000,000,001
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Richard Goldman