Editing Byte (section)

== Etymology and history <span class="anchor" id="History"></span> ==
The term ''byte'' was coined by [[Werner Buchholz]] in June 1956,<ref name="Buchholz_1956_1" /><ref name="Buchholz_1977" /><ref name="Timeline_1956" />{{efn|{{anchor|Note-Dates}}Many sources erroneously indicate a birthday of the term ''byte'' in July 1956, but [[Werner Buchholz]] claimed that the term would have been coined in [[#Buchholz-1977|June 1956]]. In fact, the [[#Buchholz-1956-1|earliest document]] supporting this dates from 1956-06-11. Buchholz stated that the transition to 8-bit bytes was conceived in [[#Buchholz-1977|August 1956]], but the earliest document found using this notion dates from [[#Buchholz-1956-3|September 1956]].}} during the early design phase for the [[IBM 7030|IBM Stretch]]<ref name="Buchholz_1956_2" /><ref name="Buchholz_1956_3" /><ref name="Buchholz_1962" /><ref name="Buchholz_1977" /><ref name="Timeline_1956" /><ref name="ESR" /><ref name="Bemer_2000" /> computer, which had addressing to the bit and variable field length (VFL) instructions with a byte size encoded in the instruction.<ref name="Buchholz_1977" /> It is a deliberate respelling of ''[[bite]]'' to avoid accidental mutation to ''[[bit]]''.<ref name="Buchholz_1962" /><ref name="Buchholz_1977" /><ref name="Blaauw_1959" />{{efn|Some later machines, e.g., [[Burroughs B1700]], [[CDC 3600]], DEC PDP-6, [[DEC PDP-10]] had the ability to operate on arbitrary bytes no larger than the word size.}}

Another origin of ''byte'' for bit groups smaller than a computer's word size, and in particular groups of [[Nibble (computing)|four bits]], is on record by Louis G. Dooley, who claimed he coined the term while working with [[Jules Schwartz]] and Dick Beeler on an air defense system called [[Experimental SAGE Subsector|SAGE]] at [[MIT Lincoln Laboratory]] in 1956 or 1957, which was jointly developed by [[Rand Corporation|Rand]], MIT, and IBM.<ref name="Dooley_1995_Byte" /><ref name="Ram_Byte" /> Later on, Schwartz's language [[JOVIAL]] actually used the term, but the author recalled vaguely that it was derived from [[AN/FSQ-31]].<ref name="Schwartz_Brooks_ACM" /><ref name="Ram_Byte" />

Early computers used a variety of four-bit [[binary-coded decimal]] (BCD) representations and the [[Sixbit|six-bit]] codes for printable graphic patterns common in the [[U.S. Army]] ([[FIELDATA]]) and [[United States Navy|Navy]]. These representations included alphanumeric characters and special graphical symbols. These sets were expanded in 1963 to seven bits of coding, called the [[American Standard Code for Information Interchange]] (ASCII) as the [[Federal Information Processing Standard]], which replaced the incompatible teleprinter codes in use by different branches of the U.S. government and universities during the 1960s. ASCII included the distinction of upper- and lowercase alphabets and a set of [[control character]]s to facilitate the transmission of written language as well as printing device functions, such as page advance and line feed, and the physical or logical control of data flow over the transmission media.<ref name="Bemer_2000" /> During the early 1960s, while also active in ASCII standardization, IBM simultaneously introduced in its product line of [[System/360]] the eight-bit [[Extended Binary Coded Decimal Interchange Code]] (EBCDIC), an expansion of their [[six-bit binary-coded decimal]] (BCDIC) representations{{efn|There was more than one BCD code page.}} used in earlier card punches.<ref name="ibm.com" />
The prominence of the System/360 led to the ubiquitous adoption of the eight-bit storage size,<ref name="Bemer_2000" /><ref name="Buchholz_1956_3" /><ref name="Buchholz_1977" /> while in detail the EBCDIC and ASCII encoding schemes are different.

In the early 1960s, [[AT&T]] introduced [[digital telephony]] on long-distance [[trunk line]]s. These used the eight-bit [[μ-law algorithm|μ-law encoding]]. This large investment promised to reduce transmission costs for eight-bit data.

In Volume 1 of ''[[The Art of Computer Programming]]'' (first published in 1968), [[Donald Knuth]] uses ''byte'' in his hypothetical [[MIX (abstract machine)|MIX]] computer to denote a unit which "contains an ''unspecified'' amount of information ... capable of holding at least 64 distinct values ... ''at most'' 100 distinct values. On a binary computer a byte must therefore be composed of six bits".<ref name="Knuth-1">{{cite book|last=Knuth|first=Donald|date=1997|title = The Art of Computer Programming: Volume 1: Fundamental Algorithms|location=Boston|publisher=Addison-Wesley|page=125|isbn=9780201896831|orig-date=1968|edition=3rd}}</ref> He notes that "Since 1975 or so, the word ''byte'' has come to mean a sequence of precisely eight binary digits...When we speak of bytes in connection with MIX we shall confine ourselves to the former sense of the word, harking back to the days when bytes were not yet standardized."<ref name="Knuth-1"/>

The development of [[eight-bit]] [[microprocessor]]s in the 1970s popularized this storage size. Microprocessors such as the [[Intel 8080]], the direct predecessor of the [[Intel 8086|8086]], could also perform a small number of operations on the [[4bit|four-bit]] pairs in a byte, such as the decimal-add-adjust (DAA) instruction. A four-bit quantity is often called a [[nibble]], also ''nybble'', which is conveniently represented by a single [[hexadecimal]] digit.

The term ''[[Octet (computing)|octet]]'' unambiguously specifies a size of eight bits.<ref name="Bemer_2000" /><ref name="ISO_2382-4" /> It is used extensively in [[Protocol (computing)|protocol]] definitions.

Historically, the term ''octad'' or ''octade'' was used to denote eight bits as well at least in Western Europe;<ref name="Williams_1969" /><ref name="Philips_1971" /> however, this usage is no longer common. The exact origin of the term is unclear, but it can be found in British, Dutch, and German sources of the 1960s and 1970s, and throughout the documentation of [[Philips]] mainframe computers.