8/17/2019 10 Computer Unit 5

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D T REPRESENT TION

COMPUTER SCIENCE FOR 10TH CLASS (UNIT # 5)=============================================================*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=

THEORY

Question: Describe the importance of binary number system in   computers.

Digital computers respond to numbers rather than letters. The ON/OFF position of 

electronic switches corresponds to binary digits i.e. 0 and 1. So, digital computers use

binary numbers system for data representation and processing.

Question: What is meant by coding in  computers?

Coding means representing numeric or non-numeric data and instructions in binary

number system. Following types of codes are used in coding of computers: -

Binary Coded Decimal (BCD):   -In this type of coding, each decimal digit is represented by its four bit binary

equivalent. E.g. BCD code for 948 is: (1001 0100 1000)Alphanumeric  Codes:It is 6-bit code. This type of codes are used when the data and instructions contain

letters and symbols in addition to numbers. i.e. EBCDIC, ASCII, ANSI, UNICODE etc

The ASCII  Code:

It is 7-bit code used to handle alphanumeric data. An extention of 8-bits code is also

available which is called ASCII-8 code.

The EBCDIC  Code:

EBCDIC (Extended binary coded Decimal Interchange Code). It is 8-bit code and

primarily used for IBM (International Business Machine) and other compatible

computers.

Question: Describe ASCII code and EBCDIC  code?

The ASCII  Code:It is 7-bit code used to handle alphanumeric data. An extension of 8-bits code is alsoavailable which is called ASCII-8 code.The EBCDIC  Code:EBCDIC (Extended binary coded Decimal Interchange Code). It is 8-bit code and

primarily used for IBM (International Business Machine) and other compatible

computers.

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