Byte

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A Byte is an Unit of Information that most commonly consists of eight bits

References

2022

  • (Wikipedia, 2022) ⇒ https://en.wikipedia.org/wiki/Byte Retrieved:2022-8-14.
    • The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer[1][2] and for this reason it is the smallest addressable unit of memory in many computer architectures. To disambiguate arbitrarily sized bytes from the common 8-bit definition, network protocol documents such as The Internet Protocol (RFC 791) refer to an 8-bit byte as an octet. Those bits in an octet are usually counted with numbering from 0 to 7 or 7 to 0 depending on the bit endianness. The first bit is number 0, making the eighth bit number 7.

      The size of the byte has historically been hardware-dependent and no definitive standards existed that mandated the size. Sizes from 1 to 48 bits have been used.[3][4][5][6] The six-bit character code was an often-used implementation in early encoding systems, and computers using six-bit and nine-bit bytes were common in the 1960s. These systems often had memory words of 12, 18, 24, 30, 36, 48, or 60 bits, corresponding to 2, 3, 4, 5, 6, 8, or 10 six-bit bytes. In this era, bit groupings in the instruction stream were often referred to as syllablesor slab, before the term byte became common.

      The modern de facto standard of eight bits, as documented in ISO/IEC 2382-1:1993, is a convenient power of two permitting the binary-encoded values 0 through 255 for one byte—2 to the power of 8 is 256.[7] The international standard IEC 80000-13 codified this common meaning. Many types of applications use information representable in eight or fewer bits and processor designers commonly optimize for this usage. The popularity of major commercial computing architectures has aided in the ubiquitous acceptance of the 8-bit byte.[8] Modern architectures typically use 32- or 64-bit words, built of four or eight bytes, respectively.

      The unit symbol for the byte was designated as the upper-case letter B by the International Electrotechnical Commission (IEC) and Institute of Electrical and Electronics Engineers (IEEE).[9] Internationally, the unit octet, symbol o, explicitly defines a sequence of eight bits, eliminating the potential ambiguity of the term "byte".[10][11]

  1. ↑ Blaauw, Gerrit Anne; Brooks, Jr., Frederick Phillips; Buchholz, Werner (1962), "4: Natural Data Units" (PDF), in Buchholz, Werner (ed.), Planning a Computer System – Project Stretch, McGraw-Hill Book Company, Inc. / The Maple Press Company, York, PA., pp. 39–40, LCCN 61-10466, archived from the original (PDF) on 2017-04-03
  2. ↑ Bemer, Robert William (1959), "A proposal for a generalized card code of 256 characters", Communications of the ACM, 2 (9): 19–23, doi:10.1145/368424.368435, S2CID 36115735
  3. ↑ Buchholz, Werner (1956-06-11). "7. The Shift Matrix" (PDF). The Link System. IBM. pp. 5–6. Stretch Memo No. 39G. Archived from the original (PDF) on 2017-04-04. Retrieved 2016-04-04.
  4. ↑ 3600 Computer System – Reference Manual (PDF). K. St. Paul, Minnesota, USA: Control Data Corporation (CDC). 1966-10-11 [1965]. 60021300. Archived from the original (PDF) on 2017-04-05. Retrieved 2017-04-05. Byte – A partition of a computer word. (NB. Discusses 12-bit, 24-bit and 48-bit bytes.)
  5. ↑ Rao, Thammavaram R. N.; Fujiwara, Eiji (1989). McCluskey, Edward J. (ed.). Error-Control Coding for Computer Systems. Prentice Hall Series in Computer Engineering (1 ed.). Englewood Cliffs, NJ, USA: Prentice Hall. ISBN 0-13-283953-9. LCCN 88-17892. (NB. Example of the usage of a code for "4-bit bytes".)
  6. ↑ Tafel, Hans Jörg (1971). Einführung in die digitale Datenverarbeitung [Introduction to digital information processing] (in German). Munich: Carl Hanser Verlag. p. 300. ISBN 3-446-10569-7. 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.)
  7. ↑ ISO/IEC 2382-1: 1993, Information technology – Vocabulary – Part 1: Fundamental terms. 1993. byte A string that consists of a number of bits, treated as a unit, and usually representing a character or a part of a character.

    NOTES

    1 The number of bits in a byte is fixed for a given data processing system.

    2 The number of bits in a byte is usually 8.

  8. ↑ "Computer History Museum – Exhibits – Internet History – 1964: Internet History 1962 to 1992". Computer History Museum. 2017 [2015]. Archived from the original on 2017-04-03. Retrieved 2017-04-03.
  9. ↑ Jaffer, Aubrey (2011) [2008]. "Metric-Interchange-Format". Archived from the original on 2017-04-03. Retrieved 2017-04-03.
  10. ↑ Kozierok, Charles M. (2005-09-20) [2001]. "The TCP/IP Guide – Binary Information and Representation: Bits, Bytes, Nibbles, Octets and Characters – Byte versus Octet". 3.0. Archived from the original on 2017-04-03. Retrieved 2017-04-03.
  11. ↑ ISO 2382-4, Organization of data (2 ed.). byte, octet, 8-bit byte: A string that consists of eight bits.
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