Slashed zero
Encyclopedia
The slashed zero is a representation of the number '0
' (zero), with a slash
through it. In character encoding
terms, it is an alternate glyph
(in addition to the open zero glyph) for the self-same zero character
. Unlike in the Scandinavian vowel
'Ø
' and the "empty set
" symbol '∅', the slash of a slashed zero usually does not extend past the ellipse (except in hasty handwriting).
The slashed zero glyph is often used to distinguish the digit "zero" ("0") from the Latin script letter "O" anywhere that the distinction is important, particularly in encoding systems, scientific and engineering applications, computer programming
(such as software development
), and telecommunications.
The Slashed zero is used in many Baudot
teleprinter
applications, specifically the keytop and typepallet that combines "P" and slashed zero.
The slashed zero is used in many ASCII graphic sets descended from the default typewheel on the Teletype
Model 33.
ø
in the name of the Hawkwind
-influenced 1980s space-rock band Underground Zerø
may have been inspired by the usage of the slashed zero by many computer systems of the time; which resembled ø (see “Heavy metal umlaut
”).
The slashed zero, sometimes called communications zero, was used on teleprinter circuits for weather applications.
The slashed zero symbol is widely used in written Amateur radio
callsigns, codes for video-games, software product keys, and any other instance when clarity is necessary.
When personal computers started to become mainstream in the early 1980s, it became one of the things associated with the hacker culture
of the time. Some cartoons depicted computer users talking in binary code
with 1s and 0s using a slashed zero for the 0.
Slashed zeroes can also be used on cheques in order to prevent fraud, for example: changing a 0 to an 8.
parlance). It is treated literally as "a zero that is slashed" and it is coded as two characters, the commonplace zero and then the "combining long solidus overlay"
When used in HTML
, use of these combining characters is valid but not yet supported by all current web browsers; for instance, Microsoft Internet Explorer fails to render them. They may be coded as
However the unslashed zero has the disadvantage that it is easily confused with the letter 'O'.
In paper writing one may not distinguish the 0 and O at all, or may add a slash across it in order to show the difference, although this sometimes causes ambiguity in regard to the symbol for the empty set
.
controllers. The dotted zero may appear similar to the Greek letter
theta
(particularly capital theta, Θ), but the two have different glyphs. In raster
fonts, the theta usually has a horizontal line connecting, or nearly touching, the sides of an O; while the dotted zero simply has a dot in the middle. However, on a low-definition display, such a form can be confused with a numeral 8.
Alternatively, the dot can become a vertical trace, for example by adding a “combining short vertical line overlay”
(and a few other early mainframe makers) used a convention in which the letter O has a slash and the digit 0 does not. This is even more problematic for Danes, Faroese
, and Norwegians because it means two of their letters—the O and slashed O (Ø
)—are similar.
The slashed zero is also common in recording amateur radio call signs for logs of contacts to distinguish a zero (i.e. Ø) from a capital 'O'.
equipment displays a zero with a reversed slash, as ⃠.
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Yet another convention common on early line printer
s left zero unornamented but added a tail or hook to the letter-O so that it resembled an inverted Q
or cursive
capital letter-O. In the Fixedsys
typeface, the numeral 0 has two internal barbs along the lines of the slash, which can alternately be considered a narrow “S” within the zero. On German car license plates, which use the FE-Schrift
typeface, there is an “insinuated” slash in zeros: a diagonal crack just beneath the top right curvature of the zero.
s commonly included in a PC
that use the slashed zero. They include:
0 (number)
0 is both a numberand the numerical digit used to represent that number in numerals.It fulfills a central role in mathematics as the additive identity of the integers, real numbers, and many other algebraic structures. As a digit, 0 is used as a placeholder in place value systems...
' (zero), with a slash
Slash (punctuation)
The slash is a sign used as a punctuation mark and for various other purposes. It is now often called a forward slash , and many other alternative names.-History:...
through it. In character encoding
Character encoding
A character encoding system consists of a code that pairs each character from a given repertoire with something else, such as a sequence of natural numbers, octets or electrical pulses, in order to facilitate the transmission of data through telecommunication networks or storage of text in...
terms, it is an alternate glyph
Glyph
A glyph is an element of writing: an individual mark on a written medium that contributes to the meaning of what is written. A glyph is made up of one or more graphemes....
(in addition to the open zero glyph) for the self-same zero character
Character (computing)
In computer and machine-based telecommunications terminology, a character is a unit of information that roughly corresponds to a grapheme, grapheme-like unit, or symbol, such as in an alphabet or syllabary in the written form of a natural language....
. Unlike in the Scandinavian vowel
Vowel
In phonetics, a vowel is a sound in spoken language, such as English ah! or oh! , pronounced with an open vocal tract so that there is no build-up of air pressure at any point above the glottis. This contrasts with consonants, such as English sh! , where there is a constriction or closure at some...
'Ø
Ø
Ø — minuscule: "ø", is a vowel and a letter used in the Danish, Faroese, Norwegian and Southern Sami languages.It's mostly used as a representation of mid front rounded vowels, such as ø œ, except for Southern Sami where it's used as an [oe] diphtong.The name of this letter is the same as the sound...
' and the "empty set
Empty set
In mathematics, and more specifically set theory, the empty set is the unique set having no elements; its size or cardinality is zero. Some axiomatic set theories assure that the empty set exists by including an axiom of empty set; in other theories, its existence can be deduced...
" symbol '∅', the slash of a slashed zero usually does not extend past the ellipse (except in hasty handwriting).
The slashed zero glyph is often used to distinguish the digit "zero" ("0") from the Latin script letter "O" anywhere that the distinction is important, particularly in encoding systems, scientific and engineering applications, computer programming
Computer programming
Computer programming is the process of designing, writing, testing, debugging, and maintaining the source code of computer programs. This source code is written in one or more programming languages. The purpose of programming is to create a program that performs specific operations or exhibits a...
(such as software development
Software development
Software development is the development of a software product...
), and telecommunications.
Origins
The slashed zero long predates computers, and has been known to have been used in the twelfth and thirteenth centuries.The Slashed zero is used in many Baudot
Baudot
Baudot:*Marc Antoine Baudot , deputy during the French Revolution*Émile Baudot , French telegraph engineer, inventor of the Baudot code*Anatole de Baudot , French architect...
teleprinter
Teleprinter
A teleprinter is a electromechanical typewriter that can be used to communicate typed messages from point to point and point to multipoint over a variety of communication channels that range from a simple electrical connection, such as a pair of wires, to the use of radio and microwave as the...
applications, specifically the keytop and typepallet that combines "P" and slashed zero.
The slashed zero is used in many ASCII graphic sets descended from the default typewheel on the Teletype
Teleprinter
A teleprinter is a electromechanical typewriter that can be used to communicate typed messages from point to point and point to multipoint over a variety of communication channels that range from a simple electrical connection, such as a pair of wires, to the use of radio and microwave as the...
Model 33.
Usage
The use of the Scandinavian vowelVowel
In phonetics, a vowel is a sound in spoken language, such as English ah! or oh! , pronounced with an open vocal tract so that there is no build-up of air pressure at any point above the glottis. This contrasts with consonants, such as English sh! , where there is a constriction or closure at some...
ø
Ø
Ø — minuscule: "ø", is a vowel and a letter used in the Danish, Faroese, Norwegian and Southern Sami languages.It's mostly used as a representation of mid front rounded vowels, such as ø œ, except for Southern Sami where it's used as an [oe] diphtong.The name of this letter is the same as the sound...
in the name of the Hawkwind
Hawkwind
Hawkwind are an English rock band, one of the earliest space rock groups. Their lyrics favour urban and science fiction themes. They are also a noted precursor to punk rock and now are considered a link between the hippie and punk cultures....
-influenced 1980s space-rock band Underground Zerø
Underground Zerø
Underground Zerø is a British space rock band, based in Norfolk, UK. The band is also known as UZØ. While the band is often referred to as "Underground Zero" or "Underground Zer0" in print, the official name of the band includes the slashed zero in its name...
may have been inspired by the usage of the slashed zero by many computer systems of the time; which resembled ø (see “Heavy metal umlaut
Heavy metal umlaut
A metal umlaut is a diaeresis that is sometimes used gratuitously or decoratively over letters in the names of hard rock or heavy metal bands—for example those of Mötley Crüe and Motörhead...
”).
The slashed zero, sometimes called communications zero, was used on teleprinter circuits for weather applications.
The slashed zero symbol is widely used in written Amateur radio
Amateur radio
Amateur radio is the use of designated radio frequency spectrum for purposes of private recreation, non-commercial exchange of messages, wireless experimentation, self-training, and emergency communication...
callsigns, codes for video-games, software product keys, and any other instance when clarity is necessary.
When personal computers started to become mainstream in the early 1980s, it became one of the things associated with the hacker culture
Hacker culture
A hacker is a member of the computer programmer subculture originated in the 1960s in the United States academia, in particular around the Massachusetts Institute of Technology 's Tech Model Railroad Club and MIT Artificial Intelligence Laboratory...
of the time. Some cartoons depicted computer users talking in binary code
Binary code
A binary code is a way of representing text or computer processor instructions by the use of the binary number system's two-binary digits 0 and 1. This is accomplished by assigning a bit string to each particular symbol or instruction...
with 1s and 0s using a slashed zero for the 0.
Slashed zeroes can also be used on cheques in order to prevent fraud, for example: changing a 0 to an 8.
Representation in Unicode and HTML
The slashed zero is supported, but not as a distinct single character (or codepoint, in UnicodeUnicode
Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...
parlance). It is treated literally as "a zero that is slashed" and it is coded as two characters, the commonplace zero and then the "combining long solidus overlay"
(U+0338). These combining characters overlay the preceding character, giving the effect of the slashed zero.When used in HTML
HTML
HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....
, use of these combining characters is valid but not yet supported by all current web browsers; for instance, Microsoft Internet Explorer fails to render them. They may be coded as
0̸ Similar symbols
The slashed zero has the disadvantage that it can be confused with several other symbols:- The slashed zero format causes problems for certain Scandinavian languages — ØØØ — minuscule: "ø", is a vowel and a letter used in the Danish, Faroese, Norwegian and Southern Sami languages.It's mostly used as a representation of mid front rounded vowels, such as ø œ, except for Southern Sami where it's used as an [oe] diphtong.The name of this letter is the same as the sound...
is used as a letterLetter (alphabet)A letter is a grapheme in an alphabetic system of writing, such as the Greek alphabet and its descendants. Letters compose phonemes and each phoneme represents a phone in the spoken form of the language....
in the Danish, FaroeseFaroese alphabetThe Faroese alphabet consists of 29 letters derived from the Latin alphabet:- See also :* Alphabets derived from the Latin* Icelandic alphabet* Faroese language* Faroese orthography* Danish and Norwegian alphabet...
and Norwegian alphabets, where it represents ø or œ. - It also resembles the Greek lettersGreek alphabetThe Greek alphabet is the script that has been used to write the Greek language since at least 730 BC . The alphabet in its classical and modern form consists of 24 letters ordered in sequence from alpha to omega...
Theta and PhiPhi (letter)Phi , pronounced or sometimes in English, and in modern Greek, is the 21st letter of the Greek alphabet. In modern Greek, it represents , a voiceless labiodental fricative. In Ancient Greek it represented , an aspirated voiceless bilabial plosive...
in some fonts (although usually, the slash is horizontal or vertical, respectively). - The symbol "∅" (U+2205) is used in mathematicsMathematicsMathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...
to refer to the empty setEmpty setIn mathematics, and more specifically set theory, the empty set is the unique set having no elements; its size or cardinality is zero. Some axiomatic set theories assure that the empty set exists by including an axiom of empty set; in other theories, its existence can be deduced...
. - "" (U+2300) is used as the standard symbol for diameterDiameterIn geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...
, though the official symbol is slightly stylised (the stroke is often thinner at the bottom and thicker at the top, like the club or baton shape of the exclamation point; and extends further above the o portion). - In German-speaking countries, Ø is also used as a symbol for averageAverageIn mathematics, an average, or central tendency of a data set is a measure of the "middle" value of the data set. Average is one form of central tendency. Not all central tendencies should be considered definitions of average....
value: average in German is Durchschnitt, directly translated as cut-through.
However the unslashed zero has the disadvantage that it is easily confused with the letter 'O'.
In paper writing one may not distinguish the 0 and O at all, or may add a slash across it in order to show the difference, although this sometimes causes ambiguity in regard to the symbol for the empty set
Empty set
In mathematics, and more specifically set theory, the empty set is the unique set having no elements; its size or cardinality is zero. Some axiomatic set theories assure that the empty set exists by including an axiom of empty set; in other theories, its existence can be deduced...
.
Dotted zero
The zero with a dot in the center is the most common variation today. It seems to have originated as an option on IBM 3270IBM 3270
The IBM 3270 is a class of block oriented terminals made by IBM since 1972 normally used to communicate with IBM mainframes. As such, it was the successor to the IBM 2260 display terminal. Due to the text colour on the original models, these terminals are informally known as green screen terminals...
controllers. The dotted zero may appear similar to the Greek letter
Greek alphabet
The Greek alphabet is the script that has been used to write the Greek language since at least 730 BC . The alphabet in its classical and modern form consists of 24 letters ordered in sequence from alpha to omega...
theta
Theta
Theta is the eighth letter of the Greek alphabet, derived from the Phoenician letter Teth...
(particularly capital theta, Θ), but the two have different glyphs. In raster
Raster graphics
In computer graphics, a raster graphics image, or bitmap, is a data structure representing a generally rectangular grid of pixels, or points of color, viewable via a monitor, paper, or other display medium...
fonts, the theta usually has a horizontal line connecting, or nearly touching, the sides of an O; while the dotted zero simply has a dot in the middle. However, on a low-definition display, such a form can be confused with a numeral 8.
Alternatively, the dot can become a vertical trace, for example by adding a “combining short vertical line overlay”
(U+20D3). It may be coded as 0⃓ Slashed 'O'
IBMIBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
(and a few other early mainframe makers) used a convention in which the letter O has a slash and the digit 0 does not. This is even more problematic for Danes, Faroese
Faroese people
The Faroese or Faroe Islanders are a Germanic ethnic group native to the Faeroe Islands. The Faroese are of mixed Norse and Gaelic origins.About 21,000 Faroese live in neighbouring countries, particularly in Denmark, Iceland and Norway....
, and Norwegians because it means two of their letters—the O and slashed O (Ø
Ø
Ø — minuscule: "ø", is a vowel and a letter used in the Danish, Faroese, Norwegian and Southern Sami languages.It's mostly used as a representation of mid front rounded vowels, such as ø œ, except for Southern Sami where it's used as an [oe] diphtong.The name of this letter is the same as the sound...
)—are similar.
The slashed zero is also common in recording amateur radio call signs for logs of contacts to distinguish a zero (i.e. Ø) from a capital 'O'.
Reversed slash
Some Burroughs/UnisysUnisys
Unisys Corporation , headquartered in Blue Bell, Pennsylvania, United States, and incorporated in Delaware, is a long established business whose core products now involves computing and networking.-History:...
equipment displays a zero with a reversed slash, as ⃠.
Other
Computer printer
In computing, a printer is a peripheral which produces a text or graphics of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are primarily used as local peripherals, and are attached by a printer cable or, in most new printers, a...
s left zero unornamented but added a tail or hook to the letter-O so that it resembled an inverted Q
Q
Q is the seventeenth letter of the basic modern Latin alphabet.- History :The Semitic sound value of Qôp was , a sound common to Semitic languages, but not found in English or most Indo-European ones...
or cursive
Cursive
Cursive, also known as joined-up writing, joint writing, or running writing, is any style of handwriting in which the symbols of the language are written in a simplified and/or flowing manner, generally for the purpose of making writing easier or faster...
capital letter-O. In the Fixedsys
Fixedsys
Fixedsys is a family of raster monospaced fonts. The name means fixed system, although it is often pronounced "fixed size" because its glyphs are monospace or fixed-width...
typeface, the numeral 0 has two internal barbs along the lines of the slash, which can alternately be considered a narrow “S” within the zero. On German car license plates, which use the FE-Schrift
FE-Schrift
' or ' has been the only typeface used on new vehicle registration plates of Germany since November 2000, except for plates issued to military-registered vehicles, which still use the former DIN 1451 typeface...
typeface, there is an “insinuated” slash in zeros: a diagonal crack just beneath the top right curvature of the zero.
Typefaces
There are very few typefaceTypeface
In typography, a typeface is the artistic representation or interpretation of characters; it is the way the type looks. Each type is designed and there are thousands of different typefaces in existence, with new ones being developed constantly....
s commonly included in a PC
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
that use the slashed zero. They include:
- ConsolasConsolasConsolas is a monospaced typeface, designed by Lucas de Groot. It is a part of a new suite of fonts that take advantage of Microsoft's ClearType font rendering technology. It comes with Microsoft's Windows Vista, Windows 7, Microsoft Office 2007 and Microsoft Visual Studio 2010, and is available...
in Microsoft'sMicrosoftMicrosoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
Windows VistaWindows VistaWindows Vista is an operating system released in several variations developed by Microsoft for use on personal computers, including home and business desktops, laptops, tablet PCs, and media center PCs...
, Windows 7, Microsoft Office 2007Microsoft Office 2007Microsoft Office 2007 is a Windows version of the Microsoft Office System, Microsoft's productivity suite. Formerly known as Office 12 in the initial stages of its beta cycle, it was released to volume license customers on November 30, 2006 and made available to retail customers on January 30, 2007...
and Microsoft Visual Studio 2010 - MenloMenlo (typeface)Menlo is a monospaced sans-serif typeface designed by Jim Lyles. The face first shipped with Mac OS X Snow Leopard. Menlo is based upon the Open Source font Bitstream Vera and the public domain font Deja Vu.-External links:* * *...
in Mac OS XMac OS XMac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems... - MonacoMonaco (typeface)Monaco is a monospaced sans-serif typeface designed by Susan Kare and Kris Holmes. The face shipped with all versions of Mac OS X and was already present with previous versions of the Mac operating system...
in Mac OS XMac OS XMac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems... - The Linux distribution known as Fedora ships with a tweaked variant of the Liberation typeface which features the use of a slashed zero; this is not present on most existing Linux distributions.