Byte

A byte is commonly used as a unit of storage measurement in computers. It is one of the basic integral data types in computing. The byte is often used to specify the size or amount of computer memory or storage, regardless of the type of data stored in it. Such numbers can get very large, which lead to the use of prefixes.

A byte has several meanings, all closely related:

1. A contiguous sequence of a fixed number of bits. On modern computers, an eight-bit byte is by far the most common. Certain older models have used six-, seven-, or nine-bit bytes -- for instance on the 36-bit architecture of the PDP-10. A byte is always atomic on the system, meaning that it is the smallest addressable unit. An eight-bit byte can hold 256 possible values (2⁸ = 256) -- enough to store an unsigned integer ranging from 0 to 255, a signed integer from -128 to 127, or an extended ASCII character.
2. A contiguous sequence of bits that comprises a sub-field of a longer sequence known as a word. On some computers it is possible to address bytes of arbitrary length. This usage is reflected, for example, in LDB and DPB assembler instructions for field extraction on a PDP-10, which survive as bytewise operations in Common Lisp; and in the six-bit bytes of the IBM 1401.
3. A datatype in certain programming languages. C for example defines byte to be synonymous with unsigned char -- an integer datatype capable of holding at least 256 different values.

The term byte was coined by Werner Buchholz in 1956 during the early design phase for the IBM Stretch computer. Originally it was described as one to six bits; typical I/O equipment of the period used six-bit units. The move to an eight-bit byte happened in late 1956, and this size was later adopted and promulgated as a standard by the System/360. The word was coined by mutating the word bite so it would not be accidentally misspelled as bit.

The eight-bit byte is often called an octet in formal contexts such as industry standards, as well as in networking. This is also the word used for the eight-bit quantity in many non-English languages, where the pun on bite does not translate.

Half of an eight-bit byte (four bits) is sometimes called (playfully) a nibble (sometimes spelled nybble) or more formally a hex digit. The nibble is often called a semioctet in a networking context and also by some standards organisations.

As a unit of measure, bytes is abbreviated as B; hence MB for megabytes. Likewise, the lowercase b is used for bits: hence, a 5 Mb/s network segment carries five megabits per second, while a 90 GB hard drive carries 90 gigabytes. Computer memory and storage are usually denominated in bytes, while network speed is denominated in bits, and parallel bus speed in hertz.

Standards organizations have proposed binary prefixes for the powers of two often used as multiples of bytes, e.g., mebibyte rather than megabyte for 2²⁰ bytes -- but these have not caught on in common usage.

A comparative table of base-10 and base-2 bytes

• 1 kilobyte [kB] = 1000 (10³) byte
• 1 megabyte [MB] = 1 000 000 (10⁶) byte
• 1 gigabyte [GB] = 1 000 000 000 (10⁹) byte
• 1 terabyte [TB] = 1 000 000 000 000 (10¹²) byte
• 1 petabyte [PB] = 1 000 000 000 000 000 (10¹⁵) byte

• 1 kibibyte [KiB] = 1024 (2¹⁰) byte
• 1 mebibyte [MiB] = 1 048 576 (2²⁰) byte
• 1 gibibyte [GiB] = 1 073 741 824 (2³⁰) byte
• 1 tebibyte [TiB] = 1 099 511 627 776 (2⁴⁰) byte
• 1 pebibyte [PiB] = 1 125 899 906 842 624 (2⁵⁰) byte

Byte was also the name of a popular computer industry magazine, see Byte magazine.

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Byte magazine

(From Wikipedia, the free Encyclopedia)

BYTE magazine was probably the most influentual microcomputer magazine in the late 1970s and the 1980s because of its wide-ranging editorial coverage. Where many magazines are dedicated to PCss, or Windows, or the Macintosh, BYTE covered developments in the entire field of "small computers and software."

BYTE started in 1975, shortly after the first personal computers appeared as kits in the back of electronics magazines. It was founded by Wayne Green, based out of Peterborough, New Hampshire. Wayne Green started a number of other popular electronics magazines with targeted audiences, such as "73," a magazine for amateur radio operators. BYTE was published monthly, with a yearly subscription price of $10. Carl Helmers was the first editor. Green and Helmers were able to attract advertising and articles from many well-knowns, soon-to-be-well-knowns, and ultimately-to-be-forgottens in the growing microcomputer hobby. Articles in the first issue (September, 1975) included "Which Microprocessor For You?" by Hal Chamberlin, "Write Your Own Assembler" by Dan Flystra and "Serial Interface" by Don Lancaster. MITS, Godbout, SCELBI, Processor Technology and Sphere were among the advertisers in that issue.

Early articles in BYTE were do-it-yourself electronic or software projects to improve one's computer. A continuing feature was "Ciarcia's Circuit Cellar," a column in which an electronic engineer described small projects to attach to one's computer (later spun off to become the magazine Circuit Cellar, focusing on embedded computer applications). Significant articles in this period included insertion of disk drives into S-100 computers, publication of source code for various computer languages (tinyC, BASIC, assemblers), and breathless coverage of the first microcomputer OS, CP/M. BYTE ran Microsoft's first advertisement, as "Micro-Soft," to sell a BASIC interpreter for 8080-based computers.

About 1978, the magazine was sold, and Wayne Green ceased to be publisher. Shortly after the IBM PC was introduced, in 1981, the magazine changed editorial policies. It dropped the do-it-yourself electronics and software articles, and began running product reviews, the first computer magazine to do so. It continued its wide-ranging coverage of hardware and software, but now it reported "what it does" and "how it works," not "how-to-do-it." The editorial focus remained on any computer system or software that might be within a typical individual's finances and interest (centered around home computers and personal computers).

BYTE continued to grow. By 1990, it was a monthly with more than a hundred pages, a readership of technical professionals, and a subscription price of $56/year (quite princely). It was the "must-read" magazine of the popular computer magazines. Around 1993, BYTE began to develop a web presence. It acquired a domain name "byte.com" and began to have discussions and post selected editorial content.

In 1998, still growing, BYTE was purchased by CMP Media, a successful publisher of specialized computer magazines. CMP ceased publication (ending with the July 1998 issue), laid off all the staff and shut down BYTE's rather large product-testing lab. Subscribers were offered a choice of two of CMP's other magazines, notably CMP's flagship publication about Windows PCs. Subscribers were shocked, horrified, and angrily speculated on the Internet that CMP had purchased BYTE to destroy it as a competitor. Publication of BYTE in Germany and Japan continued uninterrupted.

Many of BYTE's columnists migrated their writing to personal web sites. The most popular of these was probably science fiction author Jerry Pournelle's weblog "The View From Chaos Manor" derived from a long-standing column in BYTE, describing computers from a power-user's point of view. Pournelle's writing is clear, intelligent, colorful, opinionated, and idiosyncratic; he amuses or offends many people. In 1999, CMP revived BYTE as a web-publication. In 2002, the site became subscription-supported. The wide-ranging editorial policy continues. The site now has numerous articles on open-source projects, including a continuing column on Linux. Jerry Pournelle was retained to continue writing "The View From Chaos Manor."

External links

Official BYTE website:

• http://www.byte.com/

On BYTE's demise:

• http://www.gamesdomain.com/gdreview/depart/jun98/byte.html
• http://www.halfhill.com/bytefaq.html