EBCDIC: Encyclopedia II - EBCDIC - History

EBCDIC - History

EBCDIC was devised in 1963 and 1964 by IBM and was announced with the release of the IBM System/360 line of mainframe computers. It was created to extend the Binary-Coded Decimal that existed at the time. EBCDIC was developed separately from ASCII. EBCDIC is an 8-bit encoding, versus the 7-bit encoding of ASCII.

All IBM mainframe peripherals and operating systems use EBCDIC. Their operating systems provide ASCII and Unicode modes for translating between different encodings. Translation can occur within the hardware peripheral or in the software as required by the application.

At the time it was devised, EBCDIC made it relatively easy to enter data into a computer with punch cards. Since punch cards are almost never used on mainframes anymore, EBCDIC is used in modern mainframes solely for backwards compatibility. It has no technical advantage over ASCII-based code pages such as the ISO-8859 series or Unicode. As with single-byte extended ASCII codepages, most EBCDIC codepages only allow up to 2 languages (English and one other language) to be used in a database or text file.

Where true support for multilingual text is desired, a system supporting far more characters is needed. Generally this is done with some form of Unicode support. There is an EBCDIC Unicode Transformation Format called UTF-EBCDIC proposed by the Unicode consortium, but it is not intended to be used in open interchange environments, and even on EBCDIC based systems, it is almost never used. IBM mainframes have some support for UTF-16, but they do not support UTF-EBCDIC natively.

Adapted from the Wikipedia article "History", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki