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Bit : Bit : is the basic unit of information in computing and telecommunications; it is the amount of information that can be stored by a device or other physical system that can normally exist in only two distinct states (0 or 1).
1 Bit
2 Bit
2 Bit = 2² = 4 (Alternatives)
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01
0 1
0 1
Alternatives
(A,B)
1 (0,0)
2 (0,1)
3 (1,0)
4 (1,1)
Truth TableTruth Table
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3 Bit
3Bit = 2³= 8(Alternatives)
0 1
0 1
Alternatives
(A,B)
1 (0,0,0)
2 (0,0,1)
3 (0,1,0)
4 (0,1,1)
5 (1,0,0)
6 (1,1,0)
7 (1,0,1)
8 (1,1,1)
Truth TableTruth Table
0 1
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4 Bit
4 Bit = 2 = 16 (Alternatives)
5 Bit
5 Bit = 2=32 (Alternatives)
0 1
0 1
0 1
0 1
0 1
0 1
0 1
0 1
0 1
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6 Bit = 64 (Alternatives)7Bit= 128 (Alternatives)8Bit = 256(Alternatives) = 1
Byte
0 1
0 1
0 1
0 1
0 1
0 1
0 1
0 1
ASCII Code Changed to 1 Byte to be understood by the computer
system
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ASCII Code :ASCII Code :Is The American Standard Code for Information InterchangeLook to Lec11MM.doc
1 Character ------ 1 Character ------ ASCII Code ------- 1 ASCII Code ------- 1 Byte ----- 8 BitByte ----- 8 Bit
Every character has its own Every character has its own ASCII Code ASCII Code = 1 Byte= 1 Byte
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…….……….………….……….
ASCII ASCII CodeCode
1 Byte1 Byte8 Bit8 Bit
Universal Code: Universal Code: In computer architecture, 16-bit In computer architecture, 16-bit
integers, memory addresses, or other integers, memory addresses, or other data units are those that are at most 16 data units are those that are at most 16 bits (2 octets) wide.bits (2 octets) wide.
A 16-bit file format is a binary file A 16-bit file format is a binary file format for which each data element is format for which each data element is defined on 16 bits (or 2 Bytes). An defined on 16 bits (or 2 Bytes). An example of such a format is UTF-16 and example of such a format is UTF-16 and the Windows Metafile Formatthe Windows Metafile Format
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The 16-bit Intel architecture allows for The 16-bit Intel architecture allows for different memory models ways to access different memory models ways to access a particular memory location. The reason a particular memory location. The reason for using a specific memory model is the for using a specific memory model is the size of the assembler instructions or size of the assembler instructions or required storage for pointers. required storage for pointers.
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Compilers of the 16-bit era generally had Compilers of the 16-bit era generally had the following type width characteristic:the following type width characteristic:
““Tiny” Tiny” Code and data will be in the same segment
(especially, the registers CS,DS,ES,SS will point to the same segment);“near” pointers are always used. Code, data and stack together cannot exceed 64K.
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Data model Short
Int Long Pointer
IP16L32(near)
16 16 32 16
I16LP32(far) 16 16 32 32
““SSmallmall”Code and data will be in different segments, and “near”
pointers are always used. There will be 64K of space for code and 64K for data/stack.
““MediumMedium”
Code pointers will use “far” pointers, enabling access to 1MB. Data pointers remain to be of the “near” type.
““Compact” Compact” Data pointers will use “far” and code will use “near”
pointers. ““Large”/“Huge” Large”/“Huge” Code and data pointers will be “far”.
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Case study:Case study:An archive CONSISTS of A4 Paper (40 Lines
and each Line have 80 characters)AN average rate for data entry is 60 Lines
(free of errors)per one hour Calculate:Calculate:
Page contains Page contains
= amount of lines * amount of character in = amount of lines * amount of character in each lineeach line
=40*80 = 3200 characters=40*80 = 3200 characters
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3200 characters ----- 3200 Click ----- 3200 3200 characters ----- 3200 Click ----- 3200 save in buffer ------ 3200 ASKII code ---- 3200 save in buffer ------ 3200 ASKII code ---- 3200 ByteByte
Then will enter 60 correct line * 80 characterThen will enter 60 correct line * 80 character
= 80 character/minute= 80 character/minute It means 80 character/minute ÷ 60 second 80 character/minute ÷ 60 second
= 1.3 character/second= 1.3 character/second The person will enter the paper in The person will enter the paper in
= 3200 character / page ÷80 = 3200 character / page ÷80 character/minute= 40mintecharacter/minute= 40minte
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We need to take care for :We need to take care for :
1.Time established1.Time established
2.Cost 2.Cost
3.Amount finished3.Amount finished
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2.IMAGE2.IMAGE Sources of composing an image are :Sources of composing an image are :1. Camera2. Scanner3.Mobile phone OCR Software:OCR Software:Optical Character Recognition Input Image ------- Output Character Paper ------ Scanned ----- OCR ------Text 1 minute to enter text using scanner and
OCR 40 minute to enter text using person and
keyboard
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Value of work , time Information service , Economic service ,
QoS Between at least two ( A & B ) :
Machine & machine or machine & person or person & person
Service ( Economy , Time , Cost , Quality ) Service doesn’t depend on infrastructure Information service providers ( ISD )
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