The Initial Graphics Exchange Specification (IGES) is a vendor-neutral file format that allows the digital exchange of information among computer-aided design (CAD) systems. It is an ASCII-based textual format.
109-602: The official title of IGES is Digital Representation for Communication of Product Definition Data , first published in March, 1980 by the U.S. National Bureau of Standards as NBSIR 80-1978 . Many documents (like early versions of the Defense Standards MIL-PRF-28000 and MIL-STD-1840) referred to it as ASME Y14.26M , the designation of the ANSI committee that approved IGES Version 1.0. Using IGES,
218-526: A metrology agency, the Bureau of Standards was directed by Herbert Hoover to set up divisions to develop commercial standards for materials and products. Some of these standards were for products intended for government use, but product standards also affected private-sector consumption. Quality standards were developed for products including some types of clothing, automobile brake systems and headlamps, antifreeze , and electrical safety. During World War I ,
327-476: A neutron science user facility: the NIST Center for Neutron Research (NCNR). The NCNR provides scientists access to a variety of neutron scattering instruments, which they use in many research fields (materials science, fuel cells, biotechnology, etc.). The SURF III Synchrotron Ultraviolet Radiation Facility is a source of synchrotron radiation , in continuous operation since 1961. SURF III now serves as
436-529: A shift function (like in ITA2 ), which would allow more than 64 codes to be represented by a six-bit code . In a shifted code, some character codes determine choices between options for the following character codes. It allows compact encoding, but is less reliable for data transmission , as an error in transmitting the shift code typically makes a long part of the transmission unreadable. The standards committee decided against shifting, and so ASCII required at least
545-609: A white background, but most CAD systems use a black background), one located at the origin of model space [0,0,0], two red circular arcs, and two green lines. Due to its growing international popularity (several countries, including Australia and the UK, adopted IGES as their own National Standards for PMI interoperability), support was added to the TEXT (Type 212) entity to support the ISO 8859 (Latin-1) alphabet for European characters. In
654-522: A BS (backspace). Instead, there was a key marked RUB OUT that sent code 127 (DEL). The purpose of this key was to erase mistakes in a manually-input paper tape: the operator had to push a button on the tape punch to back it up, then type the rubout, which punched all holes and replaced the mistake with a character that was intended to be ignored. Teletypes were commonly used with the less-expensive computers from Digital Equipment Corporation (DEC); these systems had to use what keys were available, and thus
763-781: A CAD user can exchange product data models in the form of circuit diagrams , wireframe , freeform surface , boundary (B-rep) or solid modeling (CSG) representations . Applications supported by IGES include traditional engineering drawings , models for analysis, and other manufacturing functions. IGES was an initiative of the United States Air Force (USAF) Integrated Computer Aided Manufacturing (ICAM) project (1976-1984). ICAM sought to develop procedures ( IDEF ), processes ( Group Technology ), and software ( CAD/CAM ) that would integrate all operations in Aerospace manufacturing and thus greatly reduce costs. Earlier
872-582: A NIST team as part of a DARPA competition. In September 2013, both The Guardian and The New York Times reported that NIST allowed the National Security Agency (NSA) to insert a cryptographically secure pseudorandom number generator called Dual EC DRBG into NIST standard SP 800-90 that had a kleptographic backdoor that the NSA can use to covertly predict the future outputs of this pseudorandom number generator thereby allowing
981-458: A character count followed by the characters of the line and which used EBCDIC rather than ASCII encoding. The Telnet protocol defined an ASCII "Network Virtual Terminal" (NVT), so that connections between hosts with different line-ending conventions and character sets could be supported by transmitting a standard text format over the network. Telnet used ASCII along with CR-LF line endings, and software using other conventions would translate between
1090-694: A combination of vacuum tubes and solid-state diode logic. About the same time the Standards Western Automatic Computer , was built at the Los Angeles office of the NBS by Harry Huskey and used for research there. A mobile version, DYSEAC , was built for the Signal Corps in 1954. Due to a changing mission, the "National Bureau of Standards" became the "National Institute of Standards and Technology" in 1988. Following
1199-488: A draft of the CSF 2.0 for public comment through November 4, 2023. NIST decided to update the framework to make it more applicable to small and medium size enterprises that use the framework, as well as to accommodate the constantly changing nature of cybersecurity. In August 2024, NIST released a final set of encryption tools designed to withstand the attack of a quantum computer. These post-quantum encryption standards secure
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#17327879014361308-640: A group of users and vendors, including Boeing, General Electric , Xerox , Computervision , Applicon and others to further develop and test this software. Though it was the practice to begin the name of ICAM developments with the word integrated (for example the IDEFs) believing that there would be rapid development of graphical exchange software, USAF decided that the IGES would be the Initial Graphics Exchange Specification not
1417-498: A line terminator. The tty driver would handle the LF to CRLF conversion on output so files can be directly printed to terminal, and NL (newline) is often used to refer to CRLF in UNIX documents. Unix and Unix-like systems, and Amiga systems, adopted this convention from Multics. On the other hand, the original Macintosh OS , Apple DOS , and ProDOS used carriage return (CR) alone as
1526-605: A line terminator; however, since Apple later replaced these obsolete operating systems with their Unix-based macOS (formerly named OS X) operating system, they now use line feed (LF) as well. The Radio Shack TRS-80 also used a lone CR to terminate lines. Computers attached to the ARPANET included machines running operating systems such as TOPS-10 and TENEX using CR-LF line endings; machines running operating systems such as Multics using LF line endings; and machines running operating systems such as OS/360 that represented lines as
1635-539: A program to provide metrology services for United States scientific and commercial users. A laboratory site was constructed in Washington, DC , and instruments were acquired from the national physical laboratories of Europe. In addition to weights and measures, the Bureau developed instruments for electrical units and for measurement of light. In 1905 a meeting was called that would be the first "National Conference on Weights and Measures". Initially conceived as purely
1744-600: A reserved device control (DC0), synchronous idle (SYNC), and acknowledge (ACK). These were positioned to maximize the Hamming distance between their bit patterns. ASCII-code order is also called ASCIIbetical order. Collation of data is sometimes done in this order rather than "standard" alphabetical order ( collating sequence ). The main deviations in ASCII order are: An intermediate order converts uppercase letters to lowercase before comparing ASCII values. ASCII reserves
1853-541: A reserved meaning. Over time this interpretation has been co-opted and has eventually been changed. In modern usage, an ESC sent to the terminal usually indicates the start of a command sequence, which can be used to address the cursor, scroll a region, set/query various terminal properties, and more. They are usually in the form of a so-called " ANSI escape code " (often starting with a " Control Sequence Introducer ", "CSI", " ESC [ ") from ECMA-48 (1972) and its successors. Some escape sequences do not have introducers, like
1962-404: A seven-bit code. The committee considered an eight-bit code, since eight bits ( octets ) would allow two four-bit patterns to efficiently encode two digits with binary-coded decimal . However, it would require all data transmission to send eight bits when seven could suffice. The committee voted to use a seven-bit code to minimize costs associated with data transmission. Since perforated tape at
2071-399: A terminal. Some operating systems such as CP/M tracked file length only in units of disk blocks, and used control-Z to mark the end of the actual text in the file. For these reasons, EOF, or end-of-file , was used colloquially and conventionally as a three-letter acronym for control-Z instead of SUBstitute. The end-of-text character ( ETX ), also known as control-C , was inappropriate for
2180-644: A user-accessible cleanroom nanomanufacturing facility. This "NanoFab" is equipped with tools for lithographic patterning and imaging (e.g., electron microscopes and atomic force microscopes ). NIST has seven standing committees: As part of its mission, NIST supplies industry, academia, government, and other users with over 1,300 Standard Reference Materials (SRMs). These artifacts are certified as having specific characteristics or component content, used as calibration standards for measuring equipment and procedures, quality control benchmarks for industrial processes, and experimental control samples. NIST publishes
2289-449: A variety of reasons, while using control-Z as the control character to end a file is analogous to the letter Z's position at the end of the alphabet, and serves as a very convenient mnemonic aid . A historically common and still prevalent convention uses the ETX character convention to interrupt and halt a program via an input data stream, usually from a keyboard. The Unix terminal driver uses
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#17327879014362398-417: A way to access this data decades from now. Today, plugin viewers for Web browsers allow IGES files created 20 years ago to be viewed from anywhere in the world. After the initial release of STEP (ISO 10303) in 1994, interest in further development of IGES declined, and Version 5.3 (1996) was the last published standard. An IGES file is composed of 80-character ASCII records, a record length derived from
2507-548: A wide range of electronic information, from confidential email messages to e-commerce transactions that propel the modern economy. Four scientific researchers at NIST have been awarded Nobel Prizes for work in physics : William Daniel Phillips in 1997, Eric Allin Cornell in 2001, John Lewis Hall in 2005 and David Jeffrey Wineland in 2012, which is the largest number for any US government laboratory not accounting for ubiquitous government contracts to state institutions and
2616-737: Is 0101 in binary). Many of the non-alphanumeric characters were positioned to correspond to their shifted position on typewriters; an important subtlety is that these were based on mechanical typewriters, not electric typewriters. Mechanical typewriters followed the de facto standard set by the Remington No. 2 (1878), the first typewriter with a shift key, and the shifted values of 23456789- were "#$ %_&'() – early typewriters omitted 0 and 1 , using O (capital letter o ) and l (lowercase letter L ) instead, but 1! and 0) pairs became standard once 0 and 1 became common. Thus, in ASCII !"#$ % were placed in
2725-479: Is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical science laboratory programs that include nanoscale science and technology , engineering , information technology , neutron research, material measurement, and physical measurement. From 1901 to 1988, the agency
2834-649: Is now the Handbook 44 since 1918 and began publication under the current name in 1949. The 2010 edition conforms to the concept of the primary use of the SI (metric) measurements recommended by the Omnibus Foreign Trade and Competitiveness Act of 1988 . NIST is developing government-wide identity document standards for federal employees and contractors to prevent unauthorized persons from gaining access to government buildings and computer systems. In 2002,
2943-575: Is providing practical guidance and tools to better prepare facility owners, contractors, architects, engineers, emergency responders, and regulatory authorities to respond to future disasters. The investigation portion of the response plan was completed with the release of the final report on 7 World Trade Center on November 20, 2008. The final report on the WTC Towers—including 30 recommendations for improving building and occupant safety—was released on October 26, 2005. NIST works in conjunction with
3052-427: Is replaced by a second control-S to resume output. The 33 ASR also could be configured to employ control-R (DC2) and control-T (DC4) to start and stop the tape punch; on some units equipped with this function, the corresponding control character lettering on the keycap above the letter was TAPE and TAPE respectively. The Teletype could not move its typehead backwards, so it did not have a key on its keyboard to send
3161-404: Is the newline problem on various operating systems . Teletype machines required that a line of text be terminated with both "carriage return" (which moves the printhead to the beginning of the line) and "line feed" (which advances the paper one line without moving the printhead). The name "carriage return" comes from the fact that on a manual typewriter the carriage holding the paper moves while
3270-579: The Aerospace industry. A serious issue was the incompatibility of data produced by the many CAD systems in use at the time. USAF/ICAM called a meeting at the National Bureau of Standards (now known as National Institute of Standards and Technology or NIST ) in 1978 to address this issue. Boeing offered to sell its CAD translation software to USAF for one United States dollar. USAF accepted this offer and contracted NIST to bring together
3379-575: The Biden administration began plans to create a U.S. AI Safety Institute within NIST to coordinate AI safety matters. According to The Washington Post , NIST is considered "notoriously underfunded and understaffed", which could present an obstacle to these efforts. NIST, known between 1901 and 1988 as the National Bureau of Standards (NBS), is a measurement standards laboratory , also known as
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3488-503: The Comité Consultatif International Téléphonique et Télégraphique (CCITT) International Telegraph Alphabet No. 2 (ITA2) standard of 1932, FIELDATA (1956 ), and early EBCDIC (1963), more than 64 codes were required for ASCII. ITA2 was in turn based on Baudot code , the 5-bit telegraph code Émile Baudot invented in 1870 and patented in 1874. The committee debated the possibility of
3597-525: The Constitution of the United States , ratified in 1789, granted these powers to the new Congress: "The Congress shall have power ... To coin money, regulate the value thereof, and of foreign coin, and fix the standard of weights and measures". In January 1790, President George Washington , in his first annual message to Congress , said, "Uniformity in the currency, weights, and measures of
3706-752: The Handbook 44 each year after the annual meeting of the National Conference on Weights and Measures (NCWM). Each edition is developed through cooperation of the Committee on Specifications and Tolerances of the NCWM and the Weights and Measures Division (WMD) of NIST. The purpose of the book is a partial fulfillment of the statutory responsibility for "cooperation with the states in securing uniformity of weights and measures laws and methods of inspection". NIST has been publishing various forms of what
3815-568: The National Construction Safety Team Act mandated NIST to conduct an investigation into the collapse of the World Trade Center buildings 1 and 2 and the 47-story 7 World Trade Center. The "World Trade Center Collapse Investigation", directed by lead investigator Shyam Sunder, covered three aspects, including a technical building and fire safety investigation to study the factors contributing to
3924-559: The National Medal of Science has been awarded to NIST researchers Cahn (1998) and Wineland (2007). Other notable people who have worked at NBS or NIST include: Since 1989, the director of NIST has been a Presidential appointee and is confirmed by the United States Senate , and since that year the average tenure of NIST directors has fallen from 11 years to 2 years in duration. Since the 2011 reorganization of NIST,
4033-737: The September 11, 2001 attacks, under the National Construction Safety Team Act (NCST), NIST conducted the official investigation into the collapse of the World Trade Center buildings. Following the 2021 Surfside condominium building collapse , NIST sent engineers to the site to investigate the cause of the collapse. In 2019, NIST launched a program named NIST on a Chip to decrease the size of instruments from lab machines to chip size. Applications include aircraft testing, communication with satellites for navigation purposes, and temperature and pressure. In 2023,
4142-870: The Technical Guidelines Development Committee of the Election Assistance Commission to develop the Voluntary Voting System Guidelines for voting machines and other election technology. In February 2014 NIST published the NIST Cybersecurity Framework that serves as voluntary guidance for organizations to manage and reduce cybersecurity risk. It was later amended and Version 1.1 was published in April 2018. Executive Order 13800, Strengthening
4251-636: The Teletype Model 33 , which used the left-shifted layout corresponding to ASCII, differently from traditional mechanical typewriters. Electric typewriters, notably the IBM Selectric (1961), used a somewhat different layout that has become de facto standard on computers – following the IBM PC (1981), especially Model M (1984) – and thus shift values for symbols on modern keyboards do not correspond as closely to
4360-842: The Treaty of the Meter , which established the International Bureau of Weights and Measures under the control of an international committee elected by the General Conference on Weights and Measures . NIST is headquartered in Gaithersburg, Maryland , and operates a facility in Boulder, Colorado , which was dedicated by President Eisenhower in 1954. NIST's activities are organized into laboratory programs and extramural programs. Effective October 1, 2010, NIST
4469-730: The United States Federal Government support ASCII, stating: I have also approved recommendations of the Secretary of Commerce [ Luther H. Hodges ] regarding standards for recording the Standard Code for Information Interchange on magnetic tapes and paper tapes when they are used in computer operations. All computers and related equipment configurations brought into the Federal Government inventory on and after July 1, 1969, must have
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4578-667: The carriage return , line feed , and tab codes. For example, lowercase i would be represented in the ASCII encoding by binary 1101001 = hexadecimal 69 ( i is the ninth letter) = decimal 105. Despite being an American standard, ASCII does not have a code point for the cent (¢). It also does not support English terms with diacritical marks such as résumé and jalapeño , or proper nouns with diacritical marks such as Beyoncé (although on certain devices characters could be combined with punctuation such as Tilde (~) and Backtick (`) to approximate such characters.) The American Standard Code for Information Interchange (ASCII)
4687-700: The proximity fuze and the standardized airframe used originally for Project Pigeon , and shortly afterwards the autonomously radar-guided Bat anti-ship guided bomb and the Kingfisher family of torpedo-carrying missiles. In 1948, financed by the United States Air Force, the Bureau began design and construction of SEAC , the Standards Eastern Automatic Computer. The computer went into operation in May 1950 using
4796-511: The punched card era. Text strings are represented in " Hollerith " format, the number of characters in the string, followed by the letter "H", followed by the text string, e.g. , "4HSLOT" (this is the text string format used in early versions of the Fortran language). Early IGES translators had problems with IBM mainframe computers because the mainframes used EBCDIC encoding for text, and some EBCDIC-ASCII translators would either substitute
4905-645: The "Reset to Initial State", "RIS" command " ESC c ". In contrast, an ESC read from the terminal is most often used as an out-of-band character used to terminate an operation or special mode, as in the TECO and vi text editors . In graphical user interface (GUI) and windowing systems, ESC generally causes an application to abort its current operation or to exit (terminate) altogether. The inherent ambiguity of many control characters, combined with their historical usage, created problems when transferring "plain text" files between systems. The best example of this
5014-582: The "help" prefix command in GNU Emacs . Many more of the control characters have been assigned meanings quite different from their original ones. The "escape" character (ESC, code 27), for example, was intended originally to allow sending of other control characters as literals instead of invoking their meaning, an "escape sequence". This is the same meaning of "escape" encountered in URL encodings, C language strings, and other systems where certain characters have
5123-401: The "line feed" function (which causes a printer to advance its paper), and character 8 represents " backspace ". RFC 2822 refers to control characters that do not include carriage return, line feed or white space as non-whitespace control characters. Except for the control characters that prescribe elementary line-oriented formatting, ASCII does not define any mechanism for describing
5232-648: The 1990s, IGES added support for the JIS encoding for Kanji ( 漢字 ) as double-byte characters ( JIS-6226 ), allowing members of the Japan Automobile Manufacturers Association (JAMA) to exchange part models with their American and European partners without loss of the Kanji text. The current version of IGES does not support Unicode 16- or 32-bit character encoding, so Arabic and other scripts (like Thai) cannot be represented. One of
5341-419: The ASCII chart in this article. Ninety-five of the encoded characters are printable: these include the digits 0 to 9 , lowercase letters a to z , uppercase letters A to Z , and punctuation symbols . In addition, the original ASCII specification included 33 non-printing control codes which originated with Teletype models ; most of these are now obsolete, although a few are still commonly used, such as
5450-679: The ASCII table as earlier keyboards did. The /? pair also dates to the No. 2, and the ,< .> pairs were used on some keyboards (others, including the No. 2, did not shift , (comma) or . (full stop) so they could be used in uppercase without unshifting). However, ASCII split the ;: pair (dating to No. 2), and rearranged mathematical symbols (varied conventions, commonly -* =+ ) to :* ;+ -= . Some then-common typewriter characters were not included, notably ½ ¼ ¢ , while ^ ` ~ were included as diacritics for international use, and < > for mathematical use, together with
5559-406: The Bureau worked on multiple problems related to war production, even operating its own facility to produce optical glass when European supplies were cut off. Between the wars, Harry Diamond of the Bureau developed a blind approach radio aircraft landing system. During World War II, military research and development was carried out, including development of radio propagation forecast methods,
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#17327879014365668-729: The Cybersecurity of Federal Networks and Critical Infrastructure , made the Framework mandatory for U.S. federal government agencies. An extension to the NIST Cybersecurity Framework is the Cybersecurity Maturity Model (CMMC) which was introduced in 2019 (though the origin of CMMC began with Executive Order 13556). It emphasizes the importance of implementing Zero-trust architecture (ZTA) which focuses on protecting resources over
5777-470: The DEL character was assigned to erase the previous character. Because of this, DEC video terminals (by default) sent the DEL character for the key marked "Backspace" while the separate key marked "Delete" sent an escape sequence ; many other competing terminals sent a BS character for the backspace key. The early Unix tty drivers, unlike some modern implementations, allowed only one character to be set to erase
5886-702: The EC-DRBG algorithm from the NIST SP 800-90 standard. In addition to these journals, NIST (and the National Bureau of Standards before it) has a robust technical reports publishing arm. NIST technical reports are published in several dozen series, which cover a wide range of topics, from computer technology to construction to aspects of standardization including weights, measures and reference data. In addition to technical reports, NIST scientists publish many journal and conference papers each year; an database of these, along with more recent technical reports, can be found on
5995-565: The Integrated Graphics Exchange Specification. Since 1988, the DoD has required that all digital product and manufacturing information (PMI) for weapons systems contracts (the engineering drawings, circuit diagrams, etc .) be delivered in electronic form such as IGES format. As a result, CAx software vendors who want to market their products to DoD subcontractors and their partners needed to support
6104-536: The NIST cryptography process because of its recognized expertise. NIST is also required by statute to consult with the NSA." Recognizing the concerns expressed, the agency reopened the public comment period for the SP800-90 publications, promising that "if vulnerabilities are found in these or any other NIST standards, we will work with the cryptographic community to address them as quickly as possible". Due to public concern of this cryptovirology attack, NIST rescinded
6213-500: The NIST website. ASCII ASCII ( / ˈ æ s k iː / ASS -kee ), an acronym for American Standard Code for Information Interchange , is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment , and other devices. ASCII has just 128 code points , of which only 95 are printable characters , which severely limit its scope. The set of available punctuation had significant impact on
6322-600: The National Metrological Institute (NMI), which is a non-regulatory agency of the United States Department of Commerce . The institute's official mission is to: Promote U.S. innovation and industrial competitiveness by advancing measurement science , standards , and technology in ways that enhance economic security and improve our quality of life . NIST had an operating budget for fiscal year 2007 (October 1, 2006 – September 30, 2007) of about $ 843.3 million. NIST's 2009 budget
6431-469: The Teletype Model 33 machine assignments for codes 17 (control-Q, DC1, also known as XON), 19 (control-S, DC3, also known as XOFF), and 127 ( delete ) became de facto standards. The Model 33 was also notable for taking the description of control-G (code 7, BEL, meaning audibly alert the operator) literally, as the unit contained an actual bell which it rang when it received a BEL character. Because
6540-511: The US national standard for source-based radiometry throughout the generalized optical spectrum. All NASA -borne, extreme-ultraviolet observation instruments have been calibrated at SURF since the 1970s, and SURF is used for the measurement and characterization of systems for extreme ultraviolet lithography . The Center for Nanoscale Science and Technology (CNST) performs research in nanotechnology , both through internal research efforts and by running
6649-655: The USAF Manufacturing Technology Program had funded the Automatically Programmed Tools (APT) language for programming Numerically Controlled (NC) machine tools. To close the data gap between parts design and manufacturing, one of the ICAM goals was to develop CAD software that would automatically generate numerical control programs for the very complex Computer Numerically Controlled (CNC) machine tools used throughout
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#17327879014366758-487: The United States is an object of great importance, and will, I am persuaded, be duly attended to." On October 25, 1791, Washington again appealed Congress: A uniformity of the weights and measures of the country is among the important objects submitted to you by the Constitution and if it can be derived from a standard at once invariable and universal, must be no less honorable to the public council than conducive to
6867-585: The change into its draft standard. The X3.2.4 task group voted its approval for the change to ASCII at its May 1963 meeting. Locating the lowercase letters in sticks 6 and 7 caused the characters to differ in bit pattern from the upper case by a single bit, which simplified case-insensitive character matching and the construction of keyboards and printers. The X3 committee made other changes, including other new characters (the brace and vertical bar characters), renaming some control characters (SOM became start of header (SOH)) and moving or removing others (RU
6976-449: The characters S, G, D, P, or T in column 73. The characteristics and geometric information for an entity is split between two sections; one in a two record, fixed-length format (the Directory Entry, or DE Section), the other in a multiple record, comma delimited format (the Parameter Data, or PD Section), as can be seen in a more human-readable representation of the file. When displayed, the user should see two yellow points (hard to see on
7085-493: The concept of "carriage return" was meaningless. IBM's PC DOS (also marketed as MS-DOS by Microsoft) inherited the convention by virtue of being loosely based on CP/M, and Windows in turn inherited it from MS-DOS. Requiring two characters to mark the end of a line introduces unnecessary complexity and ambiguity as to how to interpret each character when encountered by itself. To simplify matters, plain text data streams, including files, on Multics used line feed (LF) alone as
7194-478: The convention was so well established that backward compatibility necessitated continuing to follow it. When Gary Kildall created CP/M , he was inspired by some of the command line interface conventions used in DEC's RT-11 operating system. Until the introduction of PC DOS in 1981, IBM had no influence in this because their 1970s operating systems used EBCDIC encoding instead of ASCII, and they were oriented toward punch-card input and line printer output on which
7303-402: The country. NIST publishes the Handbook 44 that provides the "Specifications, tolerances, and other technical requirements for weighing and measuring devices". The Congress of 1866 made use of the metric system in commerce a legally protected activity through the passage of Metric Act of 1866 . On May 20, 1875, 17 out of 20 countries signed a document known as the Metric Convention or
7412-439: The director also holds the title of Under Secretary of Commerce for Standards and Technology. Fifteen individuals have officially held the position (in addition to four acting directors who have served on a temporary basis). NIST holds patents on behalf of the Federal government of the United States , with at least one of them being custodial to protect public domain use, such as one for a Chip-scale atomic clock , developed by
7521-553: The earlier five-bit ITA2 , which was also used by the competing Telex teleprinter system. Bob Bemer introduced features such as the escape sequence . His British colleague Hugh McGregor Ross helped to popularize this work – according to Bemer, "so much so that the code that was to become ASCII was first called the Bemer–Ross Code in Europe". Because of his extensive work on ASCII, Bemer has been called "the father of ASCII". On March 11, 1968, US President Lyndon B. Johnson mandated that all computers purchased by
7630-576: The earlier teleprinter encoding systems. Like other character encodings , ASCII specifies a correspondence between digital bit patterns and character symbols (i.e. graphemes and control characters ). This allows digital devices to communicate with each other and to process, store, and communicate character-oriented information such as written language. Before ASCII was developed, the encodings in use included 26 alphabetic characters, 10 numerical digits , and from 11 to 25 special graphic symbols. To include all these, and control characters compatible with
7739-497: The end-of-transmission character ( EOT ), also known as control-D, to indicate the end of a data stream. In the C programming language , and in Unix conventions, the null character is used to terminate text strings ; such null-terminated strings can be known in abbreviation as ASCIZ or ASCIIZ, where here Z stands for "zero". Other representations might be used by specialist equipment, for example ISO 2047 graphics or hexadecimal numbers. Codes 20 hex to 7E hex , known as
7848-473: The example figures, Figure 2 from Appendix A (fmeparte.igs), that has appeared in every version of IGES since Version 3.0. It uses linear, angular, and ordinate dimension entities, as well as examples of both circular and conic arcs . It is usually the first part used when testing an IGES translator, because the standard has a picture of what it should look like. National Bureau of Standards The National Institute of Standards and Technology ( NIST )
7957-579: The first 32 code points (numbers 0–31 decimal) and the last one (number 127 decimal) for control characters . These are codes intended to control peripheral devices (such as printers ), or to provide meta-information about data streams, such as those stored on magnetic tape. Despite their name, these code points do not represent printable characters (i.e. they are not characters at all, but signals). For debugging purposes, "placeholder" symbols (such as those given in ISO 2047 and its predecessors) are assigned to them. For example, character 0x0A represents
8066-514: The illustration of the LEADER (ARROW) ENTITY (Type 214) can be used as a test case for translator implementers, because it contains all 12 arrow head styles defined by the standard. These WYSIWYG example files can be distinguished by a leading "F" and trailing "X" in the file name (like f214x.igs), and this library is called the IGES X-files by members of the IGES community . Here is one of
8175-424: The import (reading) and export (writing) of IGES format files. An ANSI standard since 1980, IGES has been used in the automotive , aerospace , and shipbuilding industries. It has been used for weapons systems from Trident missile guidance systems to entire aircraft carriers . These part models may have to be used years after the vendor of the original design system has gone out of business. IGES files provide
8284-448: The keytop for the O key also showed a left-arrow symbol (from ASCII-1963, which had this character instead of underscore ), a noncompliant use of code 15 (control-O, shift in) interpreted as "delete previous character" was also adopted by many early timesharing systems but eventually became neglected. When a Teletype 33 ASR equipped with the automatic paper tape reader received a control-S (XOFF, an abbreviation for transmit off), it caused
8393-800: The local conventions and the NVT. The File Transfer Protocol adopted the Telnet protocol, including use of the Network Virtual Terminal, for use when transmitting commands and transferring data in the default ASCII mode. This adds complexity to implementations of those protocols, and to other network protocols, such as those used for E-mail and the World Wide Web, on systems not using the NVT's CR-LF line-ending convention. The PDP-6 monitor, and its PDP-10 successor TOPS-10, used control-Z (SUB) as an end-of-file indication for input from
8502-409: The national physical laboratory for the United States. Southard had previously sponsored a bill for metric conversion of the United States. President Theodore Roosevelt appointed Samuel W. Stratton as the first director. The budget for the first year of operation was $ 40,000. The Bureau took custody of the copies of the kilogram and meter bars that were the standards for US measures, and set up
8611-429: The network perimeter. ZTA utilizes zero trust principles which include "never trust, always verify", "assume breach" and "least privileged access" to safeguard users, assets, and resources. Since ZTA holds no implicit trust to users within the network perimeter, authentication and authorization are performed at every stage of a digital transaction. This reduces the risk of unauthorized access to resources. NIST released
8720-452: The previous character in canonical input processing (where a very simple line editor is available); this could be set to BS or DEL, but not both, resulting in recurring situations of ambiguity where users had to decide depending on what terminal they were using ( shells that allow line editing, such as ksh , bash , and zsh , understand both). The assumption that no key sent a BS character allowed Ctrl+H to be used for other purposes, such as
8829-515: The previous section. Code 7F hex corresponds to the non-printable "delete" (DEL) control character and is therefore omitted from this chart; it is covered in the previous section's chart. Earlier versions of ASCII used the up arrow instead of the caret (5E hex ) and the left arrow instead of the underscore (5F hex ). ASCII was first used commercially during 1963 as a seven-bit teleprinter code for American Telephone & Telegraph 's TWX (TeletypeWriter eXchange) network. TWX originally used
8938-413: The printable characters, represent letters, digits, punctuation marks , and a few miscellaneous symbols. There are 95 printable characters in total. Code 20 hex , the "space" character, denotes the space between words, as produced by the space bar of a keyboard. Since the space character is considered an invisible graphic (rather than a control character) it is listed in the table below instead of in
9047-547: The private sector. All four were recognized for their work related to laser cooling of atoms, which is directly related to the development and advancement of the atomic clock. In 2011, Dan Shechtman was awarded the Nobel Prize in chemistry for his work on quasicrystals in the Metallurgy Division from 1982 to 1984. In addition, John Werner Cahn was awarded the 2011 Kyoto Prize for Materials Science, and
9156-482: The probable cause of the collapses of the WTC Towers (WTC 1 and 2) and WTC 7. NIST also established a research and development program to provide the technical basis for improved building and fire codes, standards, and practices, and a dissemination and technical assistance program to engage leaders of the construction and building community in implementing proposed changes to practices, standards, and codes. NIST also
9265-444: The proposed Bell code and ASCII were both ordered for more convenient sorting (i.e., alphabetization) of lists and added features for devices other than teleprinters. The use of ASCII format for Network Interchange was described in 1969. That document was formally elevated to an Internet Standard in 2015. Originally based on the (modern) English alphabet , ASCII encodes 128 specified characters into seven-bit integers as shown by
9374-481: The public convenience. In 1821, President John Quincy Adams declared, "Weights and measures may be ranked among the necessities of life to every individual of human society.". Nevertheless, it was not until 1838 that the United States government adopted a uniform set of standards. From 1830 until 1901, the role of overseeing weights and measures was carried out by the Office of Standard Weights and Measures, which
9483-485: The same page for subsequent use as camera-ready copy for commercial publication. Beginning with IGES Version 5.2, this is how the standard was generated, and Version 5.3 (the most recent ANSI-approved version) is available as a PDF document. Many of the illustrations (all of which conform to the Defense Department's MIL-D-28000 Engineering Drawings Subset of IGES) use the entities that they describe, e.g.,
9592-522: The same reason, many special signs commonly used as separators were placed before digits. The committee decided it was important to support uppercase 64-character alphabets , and chose to pattern ASCII so it could be reduced easily to a usable 64-character set of graphic codes, as was done in the DEC SIXBIT code (1963). Lowercase letters were therefore not interleaved with uppercase . To keep options available for lowercase letters and other graphics,
9701-494: The second stick, positions 1–5, corresponding to the digits 1–5 in the adjacent stick. The parentheses could not correspond to 9 and 0 , however, because the place corresponding to 0 was taken by the space character. This was accommodated by removing _ (underscore) from 6 and shifting the remaining characters, which corresponded to many European typewriters that placed the parentheses with 8 and 9 . This discrepancy from typewriters led to bit-paired keyboards , notably
9810-538: The simple line characters \ | (in addition to common / ). The @ symbol was not used in continental Europe and the committee expected it would be replaced by an accented À in the French variation, so the @ was placed in position 40 hex , right before the letter A. The control codes felt essential for data transmission were the start of message (SOM), end of address (EOA), end of message (EOM), end of transmission (EOT), "who are you?" (WRU), "are you?" (RU),
9919-402: The special and numeric codes were arranged before the letters, and the letter A was placed in position 41 hex to match the draft of the corresponding British standard. The digits 0–9 are prefixed with 011, but the remaining 4 bits correspond to their respective values in binary, making conversion with binary-coded decimal straightforward (for example, 5 in encoded to 011 0101 , where 5
10028-431: The standard by NSA). NIST responded to the allegations, stating that "NIST works to publish the strongest cryptographic standards possible" and that it uses "a transparent, public process to rigorously vet our recommended standards". The agency stated that "there has been some confusion about the standards development process and the role of different organizations in it...The National Security Agency (NSA) participates in
10137-425: The standard is unclear about the meaning of "delete". Probably the most influential single device affecting the interpretation of these characters was the Teletype Model 33 ASR, which was a printing terminal with an available paper tape reader/punch option. Paper tape was a very popular medium for long-term program storage until the 1980s, less costly and in some ways less fragile than magnetic tape. In particular,
10246-440: The structure or appearance of text within a document. Other schemes, such as markup languages , address page and document layout and formatting. The original ASCII standard used only short descriptive phrases for each control character. The ambiguity this caused was sometimes intentional, for example where a character would be used slightly differently on a terminal link than on a data stream , and sometimes accidental, for example
10355-415: The surreptitious decryption of data. Both papers report that the NSA worked covertly to get its own version of SP 800-90 approved for worldwide use in 2006. The whistle-blowing document states that "eventually, NSA became the sole editor". The reports confirm suspicions and technical grounds publicly raised by cryptographers in 2007 that the EC-DRBG could contain a kleptographic backdoor (perhaps placed in
10464-515: The syntax of computer languages and text markup. ASCII hugely influenced the design of character sets used by modern computers, including Unicode which has over a million code points, but the first 128 of these are the same as ASCII. The Internet Assigned Numbers Authority (IANA) prefers the name US-ASCII for this character encoding. ASCII is one of the IEEE milestones . ASCII was developed in part from telegraph code . Its first commercial use
10573-441: The tape reader to stop; receiving control-Q (XON, transmit on) caused the tape reader to resume. This so-called flow control technique became adopted by several early computer operating systems as a "handshaking" signal warning a sender to stop transmission because of impending buffer overflow ; it persists to this day in many systems as a manual output control technique. On some systems, control-S retains its meaning, but control-Q
10682-600: The time could record eight bits in one position, it also allowed for a parity bit for error checking if desired. Eight-bit machines (with octets as the native data type) that did not use parity checking typically set the eighth bit to 0. The code itself was patterned so that most control codes were together and all graphic codes were together, for ease of identification. The first two so-called ASCII sticks (32 positions) were reserved for control characters. The "space" character had to come before graphics to make sorting easier, so it became position 20 hex ; for
10791-447: The typebars that strike the ribbon remain stationary. The entire carriage had to be pushed (returned) to the right in order to position the paper for the next line. DEC operating systems ( OS/8 , RT-11 , RSX-11 , RSTS , TOPS-10 , etc.) used both characters to mark the end of a line so that the console device (originally Teletype machines) would work. By the time so-called "glass TTYs" (later called CRTs or "dumb terminals") came along,
10900-484: The unique features of the IGES standard is that it was the first ANSI standard to be documented using itself. Since Version 4.0, all of the technical illustrations for the printed version of the standard have been generated from IGES files. The electronic publishing system ( LaTeX ) integrates raster images generated from IGES files into the PostScript sent to the laser printer , so text and images are printed on
11009-492: The wrong character, or improperly set the parity bit , causing a misread. Here is a very small IGES file from 1987, containing only two POINT (Type 116), two CIRCULAR ARC (Type 100), and two LINE (Type 110) entities. It represents a slot, with the points at the centers of the two half-circles that form the ends of the slot, and the two lines that form the sides. The file is divided into 5 sections: S tart, G lobal, D irectory Entry, P arameter Data, and T erminate indicated by
11118-523: Was $ 992 million, and it also received $ 610 million as part of the American Recovery and Reinvestment Act . NIST employs about 2,900 scientists, engineers, technicians, and support and administrative personnel. About 1,800 NIST associates (guest researchers and engineers from American companies and foreign countries) complement the staff. In addition, NIST partners with 1,400 manufacturing specialists and staff at nearly 350 affiliated centers around
11227-678: Was developed under the auspices of a committee of the American Standards Association (ASA), called the X3 committee, by its X3.2 (later X3L2) subcommittee, and later by that subcommittee's X3.2.4 working group (now INCITS ). The ASA later became the United States of America Standards Institute (USASI) and ultimately became the American National Standards Institute (ANSI). With the other special characters and control codes filled in, ASCII
11336-508: Was in the Teletype Model 33 and the Teletype Model 35 as a seven- bit teleprinter code promoted by Bell data services. Work on the ASCII standard began in May 1961, with the first meeting of the American Standards Association's (ASA) (now the American National Standards Institute or ANSI) X3.2 subcommittee. The first edition of the standard was published in 1963, underwent a major revision during 1967, and experienced its most recent update during 1986. Compared to earlier telegraph codes,
11445-489: Was named the National Bureau of Standards . The Articles of Confederation , ratified by the colonies in 1781, provided: The United States in Congress assembled shall also have the sole and exclusive right and power of regulating the alloy and value of coin struck by their own authority, or by that of the respective states—fixing the standards of weights and measures throughout the United States. Article 1, section 8, of
11554-719: Was part of the Survey of the Coast—renamed the United States Coast Survey in 1836 and the United States Coast and Geodetic Survey in 1878—in the United States Department of the Treasury . In 1901, in response to a bill proposed by Congressman James H. Southard (R, Ohio), the National Bureau of Standards was founded with the mandate to provide standard weights and measures, and to serve as
11663-695: Was published as ASA X3.4-1963, leaving 28 code positions without any assigned meaning, reserved for future standardization, and one unassigned control code. There was some debate at the time whether there should be more control characters rather than the lowercase alphabet. The indecision did not last long: during May 1963 the CCITT Working Party on the New Telegraph Alphabet proposed to assign lowercase characters to sticks 6 and 7, and International Organization for Standardization TC 97 SC 2 voted during October to incorporate
11772-619: Was realigned by reducing the number of NIST laboratory units from ten to six. NIST Laboratories include: Extramural programs include: NIST's Boulder laboratories are best known for NIST‑F1 , which houses an atomic clock . NIST‑F1 serves as the source of the nation's official time. From its measurement of the natural resonance frequency of cesium —which defines the second —NIST broadcasts time signals via longwave radio station WWVB near Fort Collins , Colorado, and shortwave radio stations WWV and WWVH , located near Fort Collins and Kekaha, Hawaii , respectively. NIST also operates
11881-450: Was removed). ASCII was subsequently updated as USAS X3.4-1967, then USAS X3.4-1968, ANSI X3.4-1977, and finally, ANSI X3.4-1986. In the X3.15 standard, the X3 committee also addressed how ASCII should be transmitted ( least significant bit first) and recorded on perforated tape. They proposed a 9-track standard for magnetic tape and attempted to deal with some punched card formats. The X3.2 subcommittee designed ASCII based on
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