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Ascii85, also called Base85, is a form of binary-to-text encoding developed by Paul E. Rutter for the btoa utility. By using five ASCII characters to represent four bytes of binary data (making the encoded size larger than the original, assuming eight bits per ASCII character), it is more efficient than uuencode or Base64, which use four characters to represent three bytes of data ( increase, assuming eight bits per ASCII character). Its main modern uses are in Adobe's PostScript and Portable Document Format file formats, as well as in the patch (Unix), patch encoding for binary files used by Git. Overview The basic need for a binary-to-text encoding comes from a need to communicate arbitrary binary data over preexisting communications protocols that were designed to carry only English language human-readable text. Those communication protocols may only be 7-bit safe (and within that avoid certain ASCII control codes), and may require line break (computing), line breaks at certai ...
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Binary-to-text Encoding
A binary-to-text encoding is code, encoding of data (computing), data in plain text. More precisely, it is an encoding of binary data in a sequence of character (computing), printable characters. These encodings are necessary for transmission of data when the communication channel does not allow binary data (such as email or NNTP) or is not 8-bit clean. Pretty Good Privacy, PGP documentation () uses the term "ASCII armor" for binary-to-text encoding when referring to Base64. Overview The basic need for a binary-to-text encoding comes from a need to communicate arbitrary binary data over preexisting communications protocols that were designed to carry only English language human-readable text. Those communication protocols may only be 7-bit safe (and within that avoid certain ASCII control codes), and may require line break (computing), line breaks at certain maximum intervals, and may not maintain whitespace (computer science), whitespace. Thus, only the 94 ASCII#ASCII printable c ...
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Data Compression
In information theory, data compression, source coding, or bit-rate reduction is the process of encoding information using fewer bits than the original representation. Any particular compression is either lossy or lossless. Lossless compression reduces bits by identifying and eliminating statistical redundancy. No information is lost in lossless compression. Lossy compression reduces bits by removing unnecessary or less important information. Typically, a device that performs data compression is referred to as an encoder, and one that performs the reversal of the process (decompression) as a decoder. The process of reducing the size of a data file is often referred to as data compression. In the context of data transmission, it is called source coding: encoding is done at the source of the data before it is stored or transmitted. Source coding should not be confused with channel coding, for error detection and correction or line coding, the means for mapping data onto a sig ...
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Extended ASCII
Extended ASCII is a repertoire of character encodings that include (most of) the original 96 ASCII character set, plus up to 128 additional characters. There is no formal definition of "extended ASCII", and even use of the term is sometimes criticized, because it can be mistakenly interpreted to mean that the American National Standards Institute (ANSI) had updated its standard to include more characters, or that the term identifies a single unambiguous encoding, neither of which is the case. The ISO standard ISO 8859 was the first international standard to formalise a (limited) expansion of the ASCII character set: of the many language variants it encoded, ISO 8859-1 ("ISO Latin 1")which supports most Western European languages is best known in the West. There are many other extended ASCII encodings (more than 220 DOS and Windows codepages). EBCDIC ("the other" major character code) likewise developed many extended variants (more than 186 EBCDIC codepages) over the decades. All ...
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End Of Medium
The C0 and C1 control code or control character sets define control codes for use in text by computer systems that use ASCII and derivatives of ASCII. The codes represent additional information about the text, such as the position of a cursor, an instruction to start a new line, or a message that the text has been received. C0 codes are the range 00 HEX–1FHEX and the default C0 set was originally defined in ISO 646 (ASCII). C1 codes are the range 80HEX–9FHEX and the default C1 set was originally defined in ECMA-48 (harmonized later with ISO 6429). The ISO/IEC 2022 system of specifying control and graphic characters allows other C0 and C1 sets to be available for specialized applications, but they are rarely used. C0 controls ASCII defines 32 control characters, plus the DEL character. This large number of codes was desirable at the time, as multi-byte controls would require implementation of a state machine in the terminal, which was very difficult with contemporary electro ...
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Leviathan (Hobbes Book)
''Leviathan or The Matter, Forme and Power of a Commonwealth Ecclesiasticall and Civil'', commonly referred to as ''Leviathan'', is a book by the English philosopher Thomas Hobbes (1588–1679), published in 1651 (revised Latin edition 1668). Its name derives from the Leviathan of the Hebrew Bible. The work concerns the structure of society and legitimate government, and is regarded as one of the earliest and most influential examples of social contract theory. Written during the English Civil War (1642–1651), it argues for a social contract and rule by an absolute sovereign. Hobbes wrote that civil war and the brute situation of a state of nature (" the war of all against all") could be avoided only by a strong, undivided government. Content Title The title of Hobbes's treatise alludes to the Leviathan mentioned in the Book of Job. In contrast to the simply informative titles usually given to works of early modern political philosophy, such as John Locke's ''Two Treatises ...
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Thomas Hobbes
Thomas Hobbes ( ; 5 April 1588 – 4 December 1679) was an English philosopher, best known for his 1651 book ''Leviathan (Hobbes book), Leviathan'', in which he expounds an influential formulation of social contract theory. He is considered to be one of the founders of modern political philosophy. In his early life, overshadowed by his father's departure following a fight, he was taken under the care of his wealthy uncle. Hobbes's academic journey began in Malmesbury#Westport St Mary, Westport, leading him to the University of Oxford, where he was exposed to classical literature and mathematics. He then graduated from the University of Cambridge in 1608. He became a tutor to the Cavendish family, which connected him to intellectual circles and initiated his extensive travels across Europe. These experiences, including meetings with figures like Galileo, shaped his intellectual development. After returning to England from France in 1637, Hobbes witnessed the destruction and br ...
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Wikipedia
Wikipedia is a free content, free Online content, online encyclopedia that is written and maintained by a community of volunteers, known as Wikipedians, through open collaboration and the wiki software MediaWiki. Founded by Jimmy Wales and Larry Sanger in 2001, Wikipedia has been hosted since 2003 by the Wikimedia Foundation, an American 501(c)(3) organization, nonprofit organization funded mainly by donations from readers. Wikipedia is the largest and most-read reference work in history. Initially available only in English language, English, Wikipedia exists list of Wikipedias, in over 340 languages. The English Wikipedia, with over  million Article (publishing), articles, remains the largest of the editions, which together comprise more than articles and attract more than 1.5 billion unique device visits and 13 million edits per month (about 5edits per second on average) . , over 25% of Wikipedia's web traffic, traffic comes from the United States, while Jap ...
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Btoa Version
Ascii85, also called Base85, is a form of binary-to-text encoding developed by Paul E. Rutter for the btoa utility. By using five ASCII characters to represent four bytes of binary data (making the encoded size larger than the original, assuming eight bits per ASCII character), it is more efficient than uuencode or Base64, which use four characters to represent three bytes of data ( increase, assuming eight bits per ASCII character). Its main modern uses are in Adobe's PostScript and Portable Document Format file formats, as well as in the patch (Unix), patch encoding for binary files used by Git. Overview The basic need for a binary-to-text encoding comes from a need to communicate arbitrary binary data over preexisting communications protocols that were designed to carry only English language human-readable text. Those communication protocols may only be 7-bit safe (and within that avoid certain ASCII control codes), and may require line break (computing), line breaks at certai ...
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8-bit Clean
''8-bit clean'' is an attribute of computer systems, communication channels, and other devices and software, that process 8-bit character encodings without treating any byte as an in-band control code. History Until the early 1990s, many programs and data transmission channels were character-oriented and treated some characters, e.g., ETX, as control characters. Others assumed a stream of seven-bit characters, with values between 0 and 127; for example, the ASCII standard used only seven bits per character, avoiding an 8-bit representation in order to save on data transmission costs. On computers and data links using 8-bit bytes, this left the top bit of each byte free for use as a parity, flag bit, or metadata control bit. 7-bit systems and data links are unable to directly handle more complex character codes which are commonplace in non- English-speaking countries with larger alphabets. Binary files of octets cannot be transmitted through 7-bit data channels directly. To ...
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Space (punctuation)
In writing, a space () is a blank area that word divider, separates words, Sentence spacing, sentences, and other written or printed glyphs (characters). Conventions for spacing vary among languages, and in some languages the spacing rules are complex. Inter-word spaces ease the reader's task of identifying words, and avoid outright ambiguities such as "now here" vs. "nowhere". They also provide convenient guides for where a human or program may start new lines. Typesetting can use spaces of varying widths, just as it can use graphic characters of varying widths. Unlike graphic characters, typeset spaces are Typographic alignment, commonly stretched in order to align text. A typewriter, on the other hand, typically has only one width for all characters, including spaces. Following widespread acceptance of the typewriter, some typewriter conventions influenced typography and the design of printed works. Computer representation of text facilitates getting around mechanical and phys ...
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