English
Etymology
From the common practice of repeating the letter "Z" as a trailer or marker because it is the last character in the English alphabet; such an alphabetic character is notionally a "zigamorph" by functional analogy. Character elements in computer codes with all bits asserted acquire special significance with w:Punched_tape|punched tape because overpunching with all holes punched is an effective means of erasing any other character.
Noun
zigamorph (originally slang, now considered standard)
- In computer science generally, a marker or flag with all bits asserted that is the last element in a table of characters or otherwise used to signal the end of data.
- In w:Baudot_code|Baudot/Murray code specifically, the "LTRS" (w:Hexadecimal|hexadecimal 1F) character.
- In US w:ASCII|ASCII code specifically, the "Delete" (w:Hexadecimal|hexadecimal 7F) w:Control_character|control character. On old w:Punched_tape|punched tape devices, this character was often labeled "Rubout."
- In w:Unicode|Unicode specifically, the all-bits asserted (U+FFFF) element which is defined to be not a valid character.
See also
Although taking its name from the last letter of the English alphabet, "zigamorph" denotes a w:Binary_numeral_system|binary numeral system encoding with all bits asserted, as distinct from a repeated block of letters ("ZZZZ") or numbers ("9999") commonly used as an ending delimiter in computing (especially in connection with w:Punched_card|punched cards) that would more properly be called a "trailer."
External links
Jargon File definition of '''zigamorph'''
ru:zigamorph
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