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Escape Sequence
In computer science, an escape sequence is a combination of characters that has a meaning other than the literal characters contained therein; it is marked by one or more preceding (and possibly terminating) characters. Examples * In C and many derivative programming languages, a string escape sequence is a series of two or more characters, starting with a backslash \. ** Note that in C a backslash immediately followed by a newline does not constitute an escape sequence, but splices physical source lines into logical ones in the second translation phase, whereas string escape sequences are converted in the fifth translation phase. ** To represent the backslash character itself, \\ can be used, whereby the first backslash indicates an escape and the second specifies that a backslash is being escaped. ** A character may be escaped in multiple different ways. Assuming ASCII encoding, the escape sequences \x5c (hexadecimal), \\, \134 (octal) and \x5C all encode the same character: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Science
Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to Applied science, practical disciplines (including the design and implementation of Computer architecture, hardware and Computer programming, software). Computer science is generally considered an area of research, academic research and distinct from computer programming. Algorithms and data structures are central to computer science. The theory of computation concerns abstract models of computation and general classes of computational problem, problems that can be solved using them. The fields of cryptography and computer security involve studying the means for secure communication and for preventing Vulnerability (computing), security vulnerabilities. Computer graphics (computer science), Computer graphics and computational geometry address the generation of images. Progr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dumb Terminals
A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. The teletype was an example of an early-day hard-copy terminal and predated the use of a computer screen by decades. Early terminals were inexpensive devices but very slow compared to punched cards or paper tape for input, yet as the technology improved and video displays were introduced, terminals pushed these older forms of interaction from the industry. A related development was time-sharing systems, which evolved in parallel and made up for any inefficiencies in the user's typing ability with the ability to support multiple users on the same machine, each at their own terminal or terminals. The function of a terminal is typically confined to transcription and input of data; a device with significant local, programmable data-processing capability may be called a "smart terminal" or fat client. A term ... [...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 "carri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Control Sequence Introducer
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. They are used in development, scientific, commercial text-based applications as well as bulletin board systems to offer standardized functionality. 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 termi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VT100
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, bidirection ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mode (user Interface)
In user interface design, a mode is a distinct setting within a computer program or any physical machine interface, in which the same user input will produce perceived results different from those that it would in other settings. Modal interface components include the Caps lock and Insert keys on the standard computer keyboard, both of which typically put the user's typing into a different mode after being pressed, then return it to the regular mode after being re-pressed. An interface that uses no modes is known as a ''modeless'' interface. Modeless interfaces avoid ''mode errors'', in which the user performs an action appropriate to one mode while in another mode, by making it impossible for the user to commit them. Definition In his book '' The Humane Interface'', Jef Raskin defines modality as follows: "An human-machine interface is modal with respect to a given gesture when (1) the current state of the interface is not the user's locus of attention and (2) the interface ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
+++ (modem)
The Hayes command set (also known as the AT command set) is a specific command language originally developed by Dennis Hayes for the Hayes Smartmodem 300 baud modem in 1981. The command set consists of a series of short text strings which can be combined to produce commands for operations such as dialing, hanging up, and changing the parameters of the connection. The vast majority of dial-up modems use the Hayes command set in numerous variations. The command set covered only those operations supported by the earliest 300 bit/s modems. When new commands were required to control additional functionality in higher speed modems, a variety of one-off standards emerged from each of the major vendors. These continued to share the basic command structure and syntax, but added any number of new commands using some sort of prefix character – & for Hayes and USR, and \ for Microcom, for instance. Many of these were re-standardized on the Hayes extensions after the introduction of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baudot Code
The Baudot code is an early character encoding for telegraphy invented by Émile Baudot in the 1870s. It was the predecessor to the International Telegraph Alphabet No. 2 (ITA2), the most common teleprinter code in use until the advent of ASCII. Each character in the alphabet is represented by a series of five bits, sent over a communication channel such as a telegraph wire or a radio signal by asynchronous serial communication. The symbol rate measurement is known as baud, and is derived from the same name. History Baudot code (ITA1) In the below table, Columns I, II, III, IV, and V show the code; the Let. and Fig. columns show the letters and numbers for the Continental and UK versions; and the sort keys present the table in the order: alphabetical, Gray and UK Baudot developed his first multiplexed telegraph in 1872 [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heuristic
A heuristic (; ), or heuristic technique, is any approach to problem solving or self-discovery that employs a practical method that is not guaranteed to be optimal, perfect, or rational, but is nevertheless sufficient for reaching an immediate, short-term goal or approximation. Where finding an optimal solution is impossible or impractical, heuristic methods can be used to speed up the process of finding a satisfactory solution. Heuristics can be mental shortcuts that ease the cognitive load of making a decision. Examples that employ heuristics include using trial and error, a rule of thumb or an educated guess. Heuristics are the strategies derived from previous experiences with similar problems. These strategies depend on using readily accessible, though loosely applicable, information to control problem solving in human beings, machines and abstract issues. When an individual applies a heuristic in practice, it generally performs as expected. However it can alternatively cre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Character Terminal
A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. The teletype was an example of an early-day hard-copy terminal and predated the use of a computer screen by decades. Early terminals were inexpensive devices but very slow compared to punched cards or paper tape for input, yet as the technology improved and video displays were introduced, terminals pushed these older forms of interaction from the industry. A related development was time-sharing systems, which evolved in parallel and made up for any inefficiencies in the user's typing ability with the ability to support multiple users on the same machine, each at their own terminal or terminals. The function of a terminal is typically confined to transcription and input of data; a device with significant local, programmable data-processing capability may be called a "smart terminal" or fat client. A te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Debugging
In computer programming and software development, debugging is the process of finding and resolving '' bugs'' (defects or problems that prevent correct operation) within computer programs, software, or systems. Debugging tactics can involve interactive debugging, control flow analysis, unit testing, integration testing, log file analysis, monitoring at the application or system level, memory dumps, and profiling. Many programming languages and software development tools also offer programs to aid in debugging, known as ''debuggers''. Etymology The terms "bug" and "debugging" are popularly attributed to Admiral Grace Hopper in the 1940s. While she was working on a Mark II computer at Harvard University, her associates discovered a moth stuck in a relay and thereby impeding operation, whereupon she remarked that they were "debugging" the system. However, the term "bug", in the sense of "technical error", dates back at least to 1878 and Thomas Edison who describes the "litt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HP 2640
The HP 2640A and other HP 264X models were block-mode "smart" and intelligent ASCII standard serial terminals produced by Hewlett-Packard using the Intel 8008 and 8080 microprocessors. History The HP 2640A was introduced in November 1974 at a list price of US$3000. Based on the Intel 8008 CPU, it had 8 KB of ROM firmware and came standard with 1 KB of RAM, expandable up to 8 KB (two 4 KB semiconductor RAM cards). In September 1975 Hewlett-Packard introduced the HP 2644A, which was an HP 2640A with mass storage (two mini-tape cartridges, 110 KB each), for US$5000. HP followed up in 1976 with the 2640B, an updated, cost-reduced version of the 2640A with a list price of US$2600, along with three international versions: the Cyrillic-oriented 2640C, the Swedish/Finnish-oriented 2640S, and the Danish/Norwegian-oriented 2640N. All of these early members of the 2640 series had the relatively slow 8008 CPU running at 700 kHz, and they were thus limited to speeds of 2400 baud. The 2640A an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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