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COMPUTER CODES. Ranjeet Prasad B.Tech(CSE). www.powerpointpresentationon.com. COMPUTER CODES. Computer use binary coding schemes to represent data internally. A group of bits represents every symbol that appears in the data. Group of bits used to represent a symbol is called a “byte”.
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COMPUTER CODES Ranjeet Prasad B.Tech(CSE) www.powerpointpresentationon.com
COMPUTER CODES • Computer use binary coding schemes to represent data internally. • A group of bits represents every symbol that appears in the data. • Group of bits used to represent a symbol is called a “byte”. • 1 byte=8 bits
TYPES OF CODES • BCD CODE • EBCDIC • ASCII • UNICODE
BCD CODE • In computing and electronic systems, binary-coded decimal (BCD) is a class of binary encodings of decimal numbers where each decimal digit is represented by a fixed number of bits, usually four or eight, although other sizes (such as six bits) have been used historically. • Special bit patterns are sometimes used for a sign or for other indications
BCD CODE • BCD represent every decimal by four bit pattern.
EBCDIC • Extended Binary Coded Decimal Interchange Code (EBCDIC) is an 8-bit character encoding used mainly on IBM mainframe and IBM midrange computer operating systems. • EBCDIC descended from the code used with punched cards and the corresponding six bit binary-coded decimal code used with most of IBM's computer peripherals of the late 1950s and early 1960s.
ASCII • The American Standard Code for Information Interchange (ASCII) is a character-encoding scheme originally based on the English alphabet that encodes 128 specified characters - the numbers 0-9, the letters a-z and A-Z, some basic punctuation symbols, some control codes that originated with Teletype machines, and a blank space - into the 7-bit binary integers.
ASCII • ASCII codes represents text in computers , communication equipments and other devices that uses text. • ASCII includes definitions for 128 characters: 33 are non-printing control characters (many now obsolete) that affect how text and space are processed and 95 printable characters, including the space (which is considered an invisible graphic).
UNICODE • Unicode provides a unique number for every character, no matter what the platform, no matter what the program, no matter what the language. • Allows for multilingual text using any or all the languages you desire.
BENEFITS UNICODE • Having just one way to process text reduces development and support costs, improves time-to-market, and allows for single version of source code. • Standards insure interoperability and portability by prescribing conformant behavior. • Easy conversion from legacy code pages.
UNICODE ENCODING FORMS • UTF-8(Unicode Transformation Format-8) • UTF-16(Unicode Transformation Format-16) • UTF-32(Unicode Transformation Format-32)
UTF-8 • This is byte oriented format having all Unicode characters represented as a variable length of one, two, three, or four bytes.
UTF-16 • This is word oriented format having all Unicode characters represented as a variable length encoding of one or two words.(1 word=16 bits)
UTF-32 • This is a double-word oriented format having all unicode characters represented as a fixed length encoding of two words.