Code page: Difference between revisions

Revision as of 20:47, 2 May 2023

Revision as of 20:47, 2 May 2023

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{{Short description|Dated classifications of computing character sets}}

{{Use dmy dates|date=January 2020|cs1-dates=y}}

In [[computing]], a '''code page''' is a [[character encoding]] and as such it is a specific association of a set of printable [[character (computing)|character]]s and [[control character]]s with unique numbers. Typically each number represents the binary value in a single byte. (In some contexts these terms are used more precisely; see {{section link|Character encoding|Character sets, character maps and code pages}}.)

In [[computing]], a '''code page''' is a [[character encoding]].

The term "code page" originated from [[IBM]]'s [[EBCDIC]]-based mainframe systems,<ref name="IBM_i_EBCDIC"/> but [[Microsoft]], [[SAP AG|SAP]],<ref name="SAP_CP"/> and [[Oracle Corporation]]<ref name="oracle.com"/> are among the vendors that use this term. The majority of vendors identify their own character sets by a name. In the case when there is a plethora of character sets (like in IBM), identifying character sets through a number is a convenient way to distinguish them. Originally, the code page numbers referred to the [[page number|''page'' number]]s in the IBM standard character set manual,<ref name="DEC_VT510"/><ref name="DEC_1994_Codepage"/><ref name="Paul_2001_CODEPAGE"/> a condition which has not held for a long time. Vendors that use a code page system allocate their own code page number to a character encoding, even if it is better known by another name; for example, [[UTF-8]] has been assigned page numbers 1208 at IBM, 65001 at Microsoft, and 4110 at SAP.

[[Hewlett-Packard]] uses a similar concept in its [[HP-UX]] operating system and its [[Printer Command Language]]<ref name="PCL"/> (PCL) protocol for printers (either for HP printers or not). The terminology, however, is different: What others call a ''character set'', HP calls a ''symbol set'', and what IBM or Microsoft call a ''code page'', HP calls a ''symbol set code''. HP developed a series of symbol sets,<ref name="PCL-Symbol"/><ref name="PCL5"/> each with an associated symbol set code, to encode both its own character sets and other vendors’ character sets.

The multitude of character sets leads many vendors to recommend [[Unicode]].

== The code page numbering system ==