字节

字节的次方单位
十进制前缀; (SI)
二进制前缀; (IEC 60027-2)
	查; 论; 编;

字节（英语：byte），通常用作电脑及手机及手表等信息计量单位，不分数据类型。^[1]^[2] 是通信和数据存储的概念。一个字节代表八个比特。从历史的观点上，“字节”表示用于编码单个字符所需要的比特数量。历史上字节长度曾基于硬件为1-48 bit不等，最初通常使用6 bit或9 bit为一字节。今日标准以8 bit作为一字节，因8为二进制整数。八个比特在一些规范（例如工业标准、计算机网络、电信技术等）中常被称为八位组。字节（byte）可缩写成B，例如MB表示megabyte；比特（bit）可缩写成b，例如Mb表示megabit（英语：megabit）。

历史

字节一词是Werner Buchholz于1956年6月在IBM Stretch计算机的早期设计阶段发明的，该计算机的寻址为位和可变字段长度（VFL）指令，指令中编码了字节大小。这是为了避免意外突变为比特而特意重写的。

参考资料

^ Blaauw, Gerrit Anne; Brooks, Jr., Frederick Phillips; Buchholz, Werner, 4: Natural Data Units, Buchholz, Werner (编), Planning a Computer System – Project Stretch (PDF), McGraw-Hill Book Company, Inc. / The Maple Press Company, York, PA.: 39–40, 1962 [2017-04-03], LCCN 61-10466, （原始内容 (PDF)存档于2017-04-03）, […] Terms used here to describe the structure imposed by the machine design, in addition to bit, are listed below.
Byte denotes a group of bits used to encode a character, or the number of bits transmitted in parallel to and from input-output units. A term other than character is used here because a given character may be represented in different applications by more than one code, and different codes may use different numbers of bits (i.e., different byte sizes). In input-output transmission the grouping of bits may be completely arbitrary and have no relation to actual characters. (The term is coined from bite, but respelled to avoid accidental mutation to bit.)
A word consists of the number of data bits transmitted in parallel from or to memory in one memory cycle. Word size is thus defined as a structural property of the memory. (The term catena was coined for this purpose by the designers of the Bull fr computer.)
Block refers to the number of words transmitted to or from an input-output unit in response to a single input-output instruction. Block size is a structural property of an input-output unit; it may have been fixed by the design or left to be varied by the program. […]
^ Bemer, Robert William, A proposal for a generalized card code of 256 characters, Communications of the ACM, 1959, 2 (9): 19–23, doi:10.1145/368424.368435

延伸阅读

Tafel, Hans Jörg. 写于RWTH, Aachen, Germany. Einführung in die digitale Datenverarbeitung [Introduction to digital information processing]. Munich, Germany: Carl Hanser Verlag. 1971: 300. ISBN 3-446-10569-7 （德语）. Byte = zusammengehörige Folge von i.a. neun Bits; davon sind acht Datenbits, das neunte ein Prüfbit (NB. Defines a byte as a group of typically 9 bits; 8 data bits plus 1 parity bit.)
Programming with the PDP-10 Instruction Set (PDF). PDP-10 System Reference Manual 1. Digital Equipment Corporation (DEC). August 1969 [2017-04-05]. （原始内容存档 (PDF)于2017-04-05）.
Computer History Museum – Exhibits – Internet History – 1964: Internet History 1962 to 1992. Computer History Museum. 2017 [2015] [2017-04-03]. （原始内容存档于2017-04-03）.
Jaffer, Aubrey. Metric-Interchange-Format. 2011 [2008] [2017-04-03]. （原始内容存档于2017-04-03）.
Kozierok, Charles M. The TCP/IP Guide – Binary Information and Representation: Bits, Bytes, Nibbles, Octets and Characters – Byte versus Octet. 3.0. 2005-09-20 [2001] [2017-04-03]. （原始内容存档于2017-04-03）.

参阅

八字节（octet）

外部链接

ГОСТ 8.417-2002 | Страница 19 （俄文）

[Buchholz_1962-1] Blaauw, Gerrit Anne; Brooks, Jr., Frederick Phillips; Buchholz, Werner, 4: Natural Data Units, Buchholz, Werner (编), Planning a Computer System – Project Stretch (PDF), McGraw-Hill Book Company, Inc. / The Maple Press Company, York, PA.: 39–40, 1962 [2017-04-03], LCCN 61-10466, （原始内容 (PDF)存档于2017-04-03）, […] Terms used here to describe the structure imposed by the machine design, in addition to bit, are listed below.
Byte denotes a group of bits used to encode a character, or the number of bits transmitted in parallel to and from input-output units. A term other than character is used here because a given character may be represented in different applications by more than one code, and different codes may use different numbers of bits (i.e., different byte sizes). In input-output transmission the grouping of bits may be completely arbitrary and have no relation to actual characters. (The term is coined from bite, but respelled to avoid accidental mutation to bit.)
A word consists of the number of data bits transmitted in parallel from or to memory in one memory cycle. Word size is thus defined as a structural property of the memory. (The term catena was coined for this purpose by the designers of the Bull fr computer.)
Block refers to the number of words transmitted to or from an input-output unit in response to a single input-output instruction. Block size is a structural property of an input-output unit; it may have been fixed by the design or left to be varied by the program. […]

[Bemer_1959-2] Bemer, Robert William, A proposal for a generalized card code of 256 characters, Communications of the ACM, 1959, 2 (9): 19–23, doi:10.1145/368424.368435

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