UTF-9

UTF-9 is a Unicode character encodings introduced by the standards document RFC 4042 in 2005. UTF-9 and its sibling UTF-18 allow for efficient coding of Unicode characters on machines based on 36-bit words, using 9 and 18 bits per code point, respectively. Although the encoding are completely valid in a technical sense, they are largely humorous, as virtually all computers designed after the early-mid 1980s use word sizes of powers of two, making these encodings largely obsolete.

Links

 * RFC 4042
 * April Fools' Day Request for Comments: Very short Wikipedia entry on RFC 4042