Central Processing Unit Part I I
description
Transcript of Central Processing Unit Part I I
Central Processing UnitPart II
Bayram Güzer
Data Representation: On/Off
• Computers are known as complex machines but the reality is they only know two things– ON (electricity turned
on)– OFF (electricity turned
off)
• The two-state on/off system is called as binary system.
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Data Representation: On/Off
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Data Representation: On/Off
• Each 0 or 1 in the binary system is called a bit (binary digit)
• The bit is the basic unit for storing data in computer memory.
• Since single bits by themselves cannot store all the numbers, letters, and special characters, a computer must process the bits together in a group called as byte.
• There are 8 bits in a byte.
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Data Representation: On/Off
• Each byte usually represents one character of data– A letter, digit or special
character.
– There are 8 bits in a byte.
• Capacity of memory and storage are expressed in term of the number of bytes data they can hold.
Binary Character Binary Character
0110000 0 1001001 I
0110001 1 1001010 J
0110010 2 1001011 K
0110011 3 1001100 L
0110100 4 1001101 M
0110101 5 1001110 N
0110110 6 1001111 O
0110111 7 1010000 P
0111000 8 1010001 Q
0111001 9 1010010 R
1000001 A 1010011 S
1000010 B 1010100 T
1000011 C 1010101 U
1000100 D 1010110 V
1000101 E 1010111 W
1000110 F 1011000 X
1000111 G 1011001 Y
1001000 H 1011010 Z
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Data Representation: On/Off
• When number of bytes come together, they are expressed as kilobytes.– It is abbreviated as KB or K.– 1 kilobyte is equal to 1024 bytes.– Ex; Old PC memories.
• A computer word, is defined as the number of bits that constitute a common unit of data, as defined by the computer system.– 32 or 64 bits for most personal computers today.
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Data Representation: On/Off
• When number of kilobytes come together, they are expressed as megabytes.– It is abbreviated as MB which also means 1 million
bytes.– 1 megabyte is equal to 1024 KB.– Ex; Diskette, cd-rom or etc…
• When number of megabytes come together, they are expressed as gigabytes.– It is abbreviated as GB which also means 1 billions of
bytes.– 1 gigabyte is equal to 1024 megabytes.– Ex; Hard disks
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Data Representation: On/Off
• B: Byte b: bit• KB: Kilobyte - Kb: Kilobit• MB: Megabyte - Mb: Megabit• GB: Gigabyte - Gb: Gigabit• 1 B = 8 b (bit)• 1 KB = 1024 B• 1 MB = 1024 KB• 1 GB = 1024 MB
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• 1024 KBps --- 1024 Kbps (128 KBps)
• 2048 KBps --- 2048 Kbps (256 KBps)
• 4096 KBps --- 4096 Kbps (512 KBps)
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8-bit Representation ?
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8-bit Representation ?
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• It is known that a collection of bits can represent a character of data– But, what particular set of bits is equivalent to
which character?
• There must be an agreement on which groups of bits represent which characters.– ASCII– EBCDIC– Unicode 12
Data Representation: On/Off
• The code called ASCII, which stands for American Standard Code for Information Interchange uses 7-bit for each character which is equivalent to 128 unique combinations.
• A more common version is ASCII-8 which is also called as extended ASCII which can represent 256 different characters.
• ASCII representation has been accepted as universal character representation in computing systems.
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Data Representation: On/Off
• EBCDIC stands for Extended Binary Coded Decimal Interchange Code– It is used primarily on IBM and IBM-compatible
mainframes
• Unicode is designed to accommodate alphabets of more than 256 characters
• Uses 16 bits to represent one character– 65,536 possible values (216)
• Requires twice as much space to store data
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Data Representation: On/OffBinary Character Binary Character
0110000 0 1001001 I
0110001 1 1001010 J
0110010 2 1001011 K
0110011 3 1001100 L
0110100 4 1001101 M
0110101 5 1001110 N
0110110 6 1001111 O
0110111 7 1010000 P
0111000 8 1010001 Q
0111001 9 1010010 R
1000001 A 1010011 S
1000010 B 1010100 T
1000011 C 1010101 U
1000100 D 1010110 V
1000101 E 1010111 W
1000110 F 1011000 X
1000111 G 1011001 Y
1001000 H 1011010 Z15
Hierarchy of Instructions
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Hierarchy of Instructions
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Hierarchy of Instructions
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Hierarchy of Instructions
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References
• Capron, H. L. (2000). Computers Tools for an Information Age.(6th ed.). New Jersey, USA: Prentice Hall.
• http://homepage.cs.uri.edu/faculty/wolfe/book/Readings/Reading04.htm
• http://en.wikipedia.org/wiki/Pulse_%28signal_processing%29• http://www.yale.edu/pclt/PCHW/clockidea.htm• http://www.camiresearch.com/Data_Com_Basics/
data_com_tutorial.html• http://en.wikipedia.org/w/index.php?title=Relational_operator• http://en.wikipedia.org/wiki/Word_(computing)• http://en.wikipedia.org/wiki/32-bit• http://tldp.org/HOWTO/Unix-and-Internet-Fundamentals-
HOWTO/core-formats.html
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