08-01-2013, 12:12 PM
Data Formats
Data Formats.ppt (Size: 1.83 MB / Downloads: 63)
Data formats
Proprietary formats
Unique to a product or company
E.g., Microsoft Word, Word Perfect
Standards (evolve in two ways):
Proprietary formats become de facto standards (e.g., Adobe PostScript)
Invented by an international standard organization (e.g., Motion Pictures Experts Group, MPEG)
ASCII Features
Developed by ANSI (American National Standards Institute)
Defined in ANSI document X3.4-1977
7-bit code
8th bit is unused (or used for a parity bit or to indicate “extended” character set)
27 = 128 different codes
Two general types of codes:
95 are “Printing” codes (displayable on a console)
33 are “Control” codes (control features of the console or communications channel)
Represents
Latin alphabet, Arabic numerals, standard punctuation characters
Plus small set of accents and other European special characters (Latin-I ASCII)
EBCDIC
8-bit code
Developed by IBM
IBM and compatible mainframes only
Rarely used today (common in archival data)
Character codes differ from ASCII
Conversion software to/from ASCII available