Explain in detail Data Representation in Computers.

Semester:-1

Unit:-3

Explain in detail Data Representation in Computers. ?

Ans:-
           All data is represented by the state of the computer's electric switches. A switch has only two possible states 'ON'and ' OFF' so it can represent only two numeric values ( IE 0 and 1). To a computer ,when a switch is 'OFF', it represents a 0; when a switch is 'ON', it represents a  1. Because computers worked based on the binary number system. This number system base is 2. It contains digits 0 and 1. The binary digit either 0 or 1 is called BIT. 
Tax codes:-
                      Early programmers realized that they needed a  standard text code that was agreeable to all of them . In such a system,  numbers would represent the  letter of the alphabet, punctuation marks,  and other symbols. This standard code system would enable any programmer to use the same combinations of numbers to represent the same individual pieces of data.  The four most popular text code systems invented are the following :
EBCDIC:- 
                   EBCDIC stands for Extended Binary coded Decimal Interchange code. EBCDIC is an eighth bit code that defineds 256 symbols. It is still used in IBM mainframe and mid-range systems , but it is rarely encountered in personal computers .
ASCII:-
              ASCII stands for the American standard code for information interchange. The ASCII character set is most commonly used in all types computers.  ASCII is an eighth-bit code that specifics characters from values from 0 to 127. 
Extended ASCII:-
                                 Extended ASCII  is an eighth bit code that specifics the characters for values from  128 to 255. The first 40 symbols represent special punctuation.  The remaining symbols are graphic symbols. 
Unicode :-
                    The Unicode Worldwide Character standard  provides up to  four bytes to represent each letter , number or symbol. With four  bytes , enough Unicode codes can be created to represent more than 4 billion different characters or symbols.  This total is enough for every unique character and symbol in the world . One major advantage that Unicode has over other text code systems is it's compatibility with ASCII  codes.  The first 256 codes in Unicode are identical to the 256 codes used by the ASCII and Extended ASCII systems.