Information Representation: Characters and ImagesInformation Representation ReviewCharacter RepresentationsASCIIASCII Code SetEBCDICEBCDIC Code TableUnicodeUnicode: The Wide-Character SetUniversal Character Set (Unicode)Unicode Latin SetAdditional Unicode PagesComparing Characters: Collating SequenceComparing StringsImage DataRastor ImagesAcknowledgementsDale RobertsDepartment of Computer and Information Science,School of Science, IUPUICSCI 230Dale Roberts, LecturerDale Roberts, [email protected]@cs.iupui.eduInformation Representation: Characters and ImagesDale RobertsInformation Representation ReviewInformation Representation ReviewAll information must be rendered into binary in order to All information must be rendered into binary in order to be stored on a computer.be stored on a computer.Prior example of binary information representations Prior example of binary information representations include positive integers, negative integers, and floating include positive integers, negative integers, and floating point.point.Besides numbers, almost all applications must store Besides numbers, almost all applications must store characters and string information.characters and string information.Images are pervasive in today’s internet world and must Images are pervasive in today’s internet world and must be rendered in binary to be handled by internet be rendered in binary to be handled by internet browsers.browsers.Crucial to make general purpose computers, computers Crucial to make general purpose computers, computers that can easily perform many different tasks, is the idea that can easily perform many different tasks, is the idea that the program is just data. Like any other that the program is just data. Like any other information, programs must be rendered into binary in information, programs must be rendered into binary in order to be stored within a computer.order to be stored within a computer.Dale RobertsCharacter RepresentationsCharacter RepresentationsASCII – PC workstationsASCII – PC workstationsEBCDIC – IBM MainframesEBCDIC – IBM MainframesUnicode – International Character setsUnicode – International Character setsDale RobertsASCIIASCIIASCIIASCIIExpanded name Expanded name American Standard Code for Information Interchange American Standard Code for Information Interchange Area covered Area covered 7-bit coded character set for information interchange 7-bit coded character set for information interchange Sponsoring body Sponsoring body American National Standards Institute (American National Standards Institute (ANSIANSI) ) Source documents Source documents Information Systems – Coded Character Sets – 7-Bit American National Standard Information Systems – Coded Character Sets – 7-Bit American National Standard Code for Information Interchange (7-Bit ASCII)Code for Information Interchange (7-Bit ASCII) Characteristics/description Characteristics/description Specifies coding of space and a set of 94 characters (letters, digits and punctuation Specifies coding of space and a set of 94 characters (letters, digits and punctuation or mathematical symbols) suitable for the interchange of basic English language or mathematical symbols) suitable for the interchange of basic English language documents. Forms the basis for most computer code sets and is the American documents. Forms the basis for most computer code sets and is the American National Version of National Version of ISO/IEC 646ISO/IEC 646. . Usage Usage Used as the basic US code set for personal and workstation computers. Used as the basic US code set for personal and workstation computers. Further details available from Further details available from ANSIANSI, 25 West 43rd Street, New York, NY 10036, USA , 25 West 43rd Street, New York, NY 10036, USA Other references Other references A list of ASCII codes can be obtained from A list of ASCII codes can be obtained from http://www.dkuug.dk/i18n/charmaps/ANSI_X3.4-1968http://www.dkuug.dk/i18n/charmaps/ANSI_X3.4-1968..Dale RobertsASCII Code SetASCII Code SetDale RobertsEBCDICEBCDICEBCDICEBCDICExpanded name Expanded name Extended Binary Coded Decimal Interchange Code Extended Binary Coded Decimal Interchange Code Area covered Area covered 8-bit coded character set for information interchange between IBM computers 8-bit coded character set for information interchange between IBM computers Sponsoring body Sponsoring body Proprietary specification developed by IBM Proprietary specification developed by IBM Characteristics/description Characteristics/description A set of national character sets for interchange of documents between IBM A set of national character sets for interchange of documents between IBM mainframes. Most EBCDIC character sets do not contain all of the characters defined mainframes. Most EBCDIC character sets do not contain all of the characters defined in the in the ASCIIASCII code set but there is a special International Reference Version (IRV) code code set but there is a special International Reference Version (IRV) code set that contains all of the characters in set that contains all of the characters in ISO/IEC 646ISO/IEC 646 (and, therefore, ASCII). Several (and, therefore, ASCII). Several national versions have been updated to support the encoding of the euro sign (in lieu national versions have been updated to support the encoding of the euro sign (in lieu of the currency sign). of the currency sign). Usage Usage Not much used outside of IBM and similar mainframe environments. When Not much used outside of IBM and similar mainframe environments. When transmitting EBCDIC files between systems care needs to be taken to ensure that the transmitting EBCDIC files between systems care needs to be taken to ensure that the systems are set up for the relevant national code set. systems are set up for the relevant national code set. Further details available from Further details available from Your local IBM office. Your local IBM office. Other references Other references Details of the most commonly used sets of EBCDIC codes can be obtained from Details of the most commonly used sets of EBCDIC codes can be obtained from http://www.dkuug.dk/i18n/charmapshttp://www.dkuug.dk/i18n/charmaps which, however, has not necessarily been which, however, has not necessarily been updated to cover the new code pages that also support the euro sign.. updated to cover the new code pages that also support the euro