EBCDIC

with the Hollerith encoding of the 1964 EBCDIC character set. Contrast at the top is enhanced to show the printed characters. The "number" punches (0–9) directly translate to the lower 4 bits of EBCDIC, though the upper 4 bits of EBCDIC are more complex. 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 is an eight-bit character encoding, developed separately from the seven-bit ASCII encoding scheme. It was created to extend the existing Binary-Coded Decimal (BCD) Interchange Code, or BCDIC, which itself was devised as an efficient means of encoding the two zone and number punches on punched cards into six bits. The distinct encoding of 's' and 'S' (using position 2 instead of 1) was maintained from punched cards where it was desirable not to have hole punches too close to each other to ensure the integrity of the physical card. While IBM was a chief proponent of the ASCII standardization committee, Not all operating systems running on IBM hardware use EBCDIC; IBM AIX, Linux on IBM Z, and Linux on Power all use ASCII, as do all operating systems that run on the IBM Personal Computer and its successors. == Compatibility with ASCII ==

There are numerous difficulties to writing software that would work in both ASCII and EBCDIC. • The gaps between letters makes simple code that worked in ASCII fail on EBCDIC. For example would print the letters from A to Z if ASCII is used, but print 41 characters (including a number of unassigned ones) in EBCDIC. • Sorting EBCDIC puts lowercase letters before uppercase letters and letters before numbers, exactly the opposite of ASCII. • Many programming languages and file formats and network protocols designed for ASCII use available punctuation marks (such as caret , tilde , square brackets, and the curly braces and ) that did not exist in EBCDIC, making translation to EBCDIC systems difficult. Workarounds such as trigraphs were used. Conversely EBCDIC had some characters such as logical not, (US cent) that were used on IBM systems and could not be translated to ASCII. The logical not character is used in the PL/I programming language, and some other IBM languages. • The EBCDIC character NL (next line) is best treated as the ASCII LF, but, as EBCDIC also contains a character called LF, this is not always done consistently. • If seven-bit ASCII is used, there was an "unused" high bit in 8-bit bytes, and many pieces of software stored other information there. Software would also pack the seven bits and discard the eighth, such as packing five seven-bit ASCII characters in a 36-bit word. On the PDP-11, bytes with the high bit set were treated as negative numbers, behavior that was copied to C, causing unexpected problems if the high bit was set. These all made it difficult to switch from ASCII to the 8-bit EBCDIC (and also made it difficult to switch to 8-bit extended ASCII encodings). == Code page layout ==

There are hundreds of EBCDIC code pages based on the original EBCDIC character encoding; there are a variety of EBCDIC code pages intended for use in different parts of the world, including code pages for non-Latin scripts such as Chinese, Japanese (e.g., EBCDIC 930, JEF, and KEIS), Korean, and Greek (EBCDIC 875). There is also a huge number of variations with the letters swapped around for no discernible reason. The table below shows the "invariant subset" of EBCDIC, which are characters that should have the same assignments on all EBCDIC code pages that use the Latin alphabet. (This includes most of the ISO/IEC 646 invariant repertoire, except the exclamation mark.) It also shows (in gray) missing ASCII and EBCDIC punctuation, located where they are in Code Page 37 (one of the code page variants of EBCDIC). The blank cells are filled with region-specific characters in the variants, but the characters in gray are often swapped around or replaced as well. Like ASCII, the invariant subset works only for languages using only the ISO basic Latin alphabet, such as English. |208|style=background:#DDD}} == Definitions of non-ASCII EBCDIC controls ==

Following are the definitions of EBCDIC control characters which either do not map onto the ASCII control characters, or have additional uses. When mapped to Unicode, these are mostly mapped to C1 control character codepoints in a manner specified by IBM's Character Data Representation Architecture (CDRA). Although the default mapping of New Line (NL) corresponds to the ISO/IEC 6429 Next Line character (NEL, U+0085, the behaviour of which is also specified, but not required, in Unicode Annex 14), most of these C1-mapped controls match neither those in the ISO/IEC 6429 C1 set, nor those in other registered C1 control sets such as ISO 6630. Although this effectively makes the non-ASCII EBCDIC controls a unique C1 control set, they are not among the C1 control sets registered in the ISO-IR registry, meaning that they do not have an assigned control set designation sequence (as specified by ISO/IEC 2022, and optionally permitted in ISO/IEC 10646 (Unicode)). Besides U+0085 (Next Line), the Unicode Standard does not prescribe an interpretation of C1 control characters, leaving their interpretation to higher level protocols (it suggests, but does not require, their ISO/IEC 6429 interpretations in the absence of use for other purposes), so this mapping is permissible in, but not specified by, Unicode. == Code pages with Latin-1 character sets ==

The following code pages have the full Latin-1 character set (ISO/IEC 8859-1). The first column gives the original code page number. The second column gives the number of the code page updated with the euro sign (€) replacing the universal currency sign (¤) (or in the case of EBCDIC 924, with the set changed to match ISO 8859-15) Different countries have different code pages because these code pages originated as code pages with country-specific character repertoires, and were later expanded to contain the entire ISO 8859-1 repertoire, meaning that a given ISO 8859-1 character may have different code point values in different code pages. They are known as Country Extended Code Pages (CECPs). == Criticism and humor ==

Open-source software advocate and software developer Eric S. Raymond writes in his Jargon File that EBCDIC was loathed by hackers, by which he meant members of a subculture of enthusiastic programmers. What is known as vendor lock-in today, is jokingly criticized in The Jargon File with the following definition: went: References to the EBCDIC character set are made in the 1979 computer game series Zork. In the "Machine Room" in Zork II, EBCDIC is used to imply an incomprehensible language: In 2021, it became public that a Belgian bank was still using EBCDIC internally in 2019. A customer insisted that the correct spelling of his surname included an umlaut, which the bank omitted, and the customer filed a complaint citing the guarantee in the General Data Protection Regulation of the right to timely "rectification of inaccurate personal data." The bank's argument included the fact that their system used EBCDIC, as well as that it did not support letters with diacritics (or lower case, for that matter). The appeals court ruled in favor of the customer. == See also ==