|
Escape Character
In computing and telecommunications, an escape character is a character that invokes an alternative interpretation on the following characters in a character sequence. An escape character is a particular case of metacharacters. Generally, the judgement of whether something is an escape character or not depends on the context. In the telecommunications field, escape characters are used to indicate that the following characters are encoded differently. This is used to alter control characters that would otherwise be noticed and acted on by the underlying telecommunications hardware, such as illegal characters. In this context, the use of escape characters is often referred to as quoting. Definition An escape character may not have its own meaning, so all escape sequences are of two or more characters. Escape characters are part of the syntax for many programming languages, data formats, and communication protocols. For a given alphabet an escape character's purpose is to star ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Illegal Character
In computer science, an illegal character is a character that is not allowed by a certain programming language, protocol, or program. To avoid illegal characters, some languages may use an escape character which is a backslash followed by another character. Examples Windows In the Windows operating system, illegal characters in file and folder names include colons, brackets, question marks, and null character The null character is a control character with the value zero. Many character sets include a code point for a null character including Unicode (Universal Coded Character Set), ASCII (ISO/IEC 646), Baudot, ITA2 codes, the C0 control code, and EB ...s. References {{reflist Character encoding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computing
Computing is any goal-oriented activity requiring, benefiting from, or creating computer, computing machinery. It includes the study and experimentation of algorithmic processes, and the development of both computer hardware, hardware and software. Computing has scientific, engineering, mathematical, technological, and social aspects. Major computing disciplines include computer engineering, computer science, cybersecurity, data science, information systems, information technology, and software engineering. The term ''computing'' is also synonymous with counting and calculation, calculating. In earlier times, it was used in reference to the action performed by Mechanical computer, mechanical computing machines, and before that, to Computer (occupation), human computers. History The history of computing is longer than the history of computing hardware and includes the history of methods intended for pen and paper (or for chalk and slate) with or without the aid of tables. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carriage Return
A carriage return, sometimes known as a cartridge return and often shortened to CR, or return, is a control character or mechanism used to reset a device's position to the beginning of a line of text. It is closely associated with the line feed and newline concepts, although it can be considered separately in its own right. Typewriters Originally, the term "carriage return" referred to a mechanism or lever on a typewriter. For machines where the type element was fixed and the paper held in a moving ''carriage'', this lever was on the left attached to the moving carriage, and operated after typing a line of text to cause the carriage to return to the far right so the type element would be aligned to the left side of the paper. The lever would also usually ''feed'' the paper to advance to the next line. Many electric typewriters such as IBM Electric or Underwood Electric made carriage return to be another key on the keyboard instead of a lever. The key was usually labeled "car ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VT220
The VT200 series is a family of computer terminals introduced by Digital Equipment Corporation (DEC) in November 1983. The VT220 was the basic version, a text-only version with multi-lingual capabilities. The VT240 added monochrome ReGIS vector graphics support to the base model, while the VT241 did the same in color. The 200 series replaced the successful VT100 series, providing more functionality in a much smaller unit with a much smaller and lighter keyboard. Like the VT100, the VT200 series implemented a large subset of ANSI X3.64. Among its major upgrades was a number of international character sets, as well as the ability to define new character sets. The VT200 series was extremely successful in the market. Released at $1,295, but later priced at $795, the VT220 offered features, packaging and price that no other serial terminal could compete with at the time. In 1986, DEC shipped 165,000 units, giving them a 42% market share, double that of the closest competitor, Wys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Escape Key
On computer keyboards, the Esc key (named ''Escape key'' in the international standard series ISO/IEC 9995) is a key used to generate the escape character (which can be represented as ASCII code 27 in decimal, Unicode U+001B, or ). The escape character, when sent from the keyboard to a computer, often is interpreted by software as "stop", "cancel" or "exit", and when sent from the computer to an external device (including many printers since the 1980s, computer terminals and Linux consoles, for example) marks the beginning of an escape sequence to specify operating modes or characteristics generally. It is now generally placed at the top left corner of the keyboard, a convention dating at least to the original IBM PC keyboard, though the key itself originated decades earlier with teletypewriters. Symbol The keyboard symbol for the ESC key (which may be used when the usual Latin lettering is not preferred for labelling the key) is standardized in ISO/IEC 9995-7 as symbo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bob Bemer
Robert William Bemer (February 8, 1920 – June 22, 2004) was a computer scientist best known for his work at IBM during the late 1950s and early 1960s. Early life and education Born in Sault Ste. Marie, Michigan, Bemer graduated from Cranbrook Kingswood School in 1936 and took a Bachelor of Arts (B.A.) in mathematics at Albion College in 1940. He earned a certificate in aeronautical engineering at Curtiss-Wright Technical Institute in 1941. Career Bemer began his career as an aerodynamicist at Douglas Aircraft Company in 1941, then worked for RAND Corporation from 1951, IBM from 1957, UNIVAC – Sperry Rand in 1965, Bull from 1965, General Electric from 1970, and Honeywell from 1974. He served on the committee which amalgamated the design for his COMTRAN language with Grace Hopper's FLOW-MATIC and thus produced the specifications for COBOL. He also served, with Hugh McGregor Ross and others, on the separate committee which defined the ASCII character codeset in 1960, c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Printer Command Language
Printer Command Language, more commonly referred to as PCL, is a page description language (PDL) developed by Hewlett-Packard as a printer protocol and has become a '' de facto'' industry standard. Originally developed for early inkjet printers in 1984, PCL has been released in varying levels for thermal, matrix, and page printers. HP-GL/2 and PJL are supported by later versions of PCL. PCL is occasionally and incorrectly said to be an abbreviation for ''Printer Control Language'' which actually is another term for page description language. PCL levels 1 through 5 overview PCL levels 1 through 5e/5c are command-based languages using control sequences that are processed and interpreted in the order they are received. At a consumer level, PCL data streams are generated by a print driver. PCL output can also be easily generated by custom applications. *PCL 1 was introduced in 1984 on the HP ThinkJet 2225 and provides basic text and graphics printing with a maximum resolution ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ANSI Escape Codes
ANSI escape sequences are a standard for in-band signaling to control cursor location, color, font styling, and other options on video text terminals and terminal emulators. Certain sequences of bytes, most starting with an ASCII escape character and a bracket character, are embedded into text. The terminal interprets these sequences as commands, rather than text to display verbatim. ANSI sequences were introduced in the 1970s to replace vendor-specific sequences and became widespread in the computer equipment market by the early 1980s. Although hardware text terminals have become increasingly rare in the 21st century, the relevance of the ANSI standard persists because a great majority of terminal emulators and command consoles interpret at least a portion of the ANSI standard. History Almost all manufacturers of video terminals added vendor-specific escape sequences to perform operations such as placing the cursor at arbitrary positions on the screen. One example is the V ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cursor (computers)
In human–computer interaction, a cursor is an indicator used to show the current position on a computer monitor or other display device that will respond to input, such as a text cursor or a mouse pointer. Etymology ''Cursor'' is Latin for 'runner'. A cursor is a name given to the transparent slide engraved with a hairline used to mark a point on a slide rule. The term was then transferred to computers through analogy. On 14 November 1963, while attending a conference on computer graphics in Reno, Nevada, Douglas Engelbart of Augmentation Research Center (ARC) first expressed his thoughts to pursue his objective of developing both hardware and software computer technology to ''augment'' human intelligence by pondering how to adapt the underlying principles of the planimeter to inputting X- and Y-coordinate data, and envisioned something like the cursor of a mouse he initially called a ''bug'', which, in a 3-point form, could have a "drop point and 2 orthogonal wheels". He w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VT102
The VT100 is a video terminal, introduced in August 1978 by Digital Equipment Corporation (DEC). It was one of the first terminals to support ANSI escape codes for cursor control and other tasks, and added a number of extended codes for special features like controlling the status lights on the keyboard. This led to rapid uptake of the ANSI standard, which became the de facto standard for hardware video terminals and later terminal emulators. The VT100 series, especially the VT102, was extremely successful in the market, and made DEC the leading terminal vendor at the time. The VT100 series was replaced by the VT200 series starting in 1983, which proved equally successful. Ultimately, over six million terminals in the VT series were sold, based largely on the success of the VT100. Description DEC's first video terminal was the VT05 (1970), succeeded by the VT50 (1974), and soon upgraded to the VT52 (1975). The VT52 featured a text display with 80 columns and 24 rows, bidirect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexadecimal
Hexadecimal (also known as base-16 or simply hex) is a Numeral system#Positional systems in detail, positional numeral system that represents numbers using a radix (base) of sixteen. Unlike the decimal system representing numbers using ten symbols, hexadecimal uses sixteen distinct symbols, most often the symbols "0"–"9" to represent values 0 to 9 and "A"–"F" to represent values from ten to fifteen. Software developers and system designers widely use hexadecimal numbers because they provide a convenient representation of binary code, binary-coded values. Each hexadecimal digit represents four bits (binary digits), also known as a nibble (or nybble). For example, an 8-bit byte is two hexadecimal digits and its value can be written as to in hexadecimal. In mathematics, a subscript is typically used to specify the base. For example, the decimal value would be expressed in hexadecimal as . In programming, several notations denote hexadecimal numbers, usually involving a prefi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Octal
Octal (base 8) is a numeral system with eight as the base. In the decimal system, each place is a power of ten. For example: : \mathbf_ = \mathbf \times 10^1 + \mathbf \times 10^0 In the octal system, each place is a power of eight. For example: : \mathbf_8 = \mathbf \times 8^2 + \mathbf \times 8^1 + \mathbf \times 8^0 By performing the calculation above in the familiar decimal system, we see why 112 in octal is equal to 64+8+2=74 in decimal. Octal numerals can be easily converted from binary representations (similar to a quaternary numeral system) by grouping consecutive binary digits into groups of three (starting from the right, for integers). For example, the binary representation for decimal 74 is 1001010. Two zeroes can be added at the left: , corresponding to the octal digits , yielding the octal representation 112. Usage In China The eight bagua or trigrams of the I Ching correspond to octal digits: * 0 = ☷, 1 = ☳, 2 = ☵, 3 = ☱, * 4 = ☶, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
