CODE Page Approach

Code pages are something that was used beginning many years before the first IBM PC was made. Code pages are a way to provide more than 256 characters when text consists entirely of characters using 8 bits. Code pages originally were created by IBM for use with their Extended Binary Coded Decimal Interchange Code (EBCDIC). EBCDIC was created in 1963 and 1964 (when the first IBM 360 was being designed) and uses 8 bits whereas ASCII uses 7 bits. I do not know when IBM first used code pages. Code pages allow 16 bits to be used for characters of a font wherein the high-order 8 bits identify a code page within the characters of the font. So code pages are similar to Unicode except code pages where designed many years before Unicode. Also, when code pages are used, strings consist of 8-bit characters and there must be something that changes the code page to be used when multiple code pages are used.

IBM implemented code pages in the PC-DOS and MS-DOS version 3.3 operating systems. So of course Windows supported them and continues to support them.

I certainly encountered code pages when I used the IBM "mainframe" word-processing system called Script. Very few people are familair with the influence that Script had on the internet; it has had much more influence than most people realize.

Hi Arun,

Code Page was used before Unicode came into existence. It was a technique to represent characters in different languages. It was a different interpretation of ASCII set which means it kept 128 characters for English and rest 128 were specifically tailored for other languages.

Disadvantages:

a. Languages like Japanese and Chinese having more than 5000 characters were difficult to represent n 128 character set.

b. Clients also need to have a support for code page.

c. It's representation is done on the basis of operating system.



Thanks