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Waveform Graphics
Waveform graphics is a simple vector graphics system introduced by Digital Equipment Corporation (DEC) on the VT52, VT55 and VT105 terminals in the mid-1970s. It was used to produce graphics output from mainframes and minicomputers. DEC used the term "waveform graphics" to refer specifically to the hardware, but it was used more generally to describe the whole system. The system was designed to use as little computer memory as possible. At any given X location it could draw two dots at given Y locations, making it suitable for producing two superimposed waveforms, line charts or histograms. Text and graphics could be mixed, and there were additional tools for drawing axes and markers. The waveform graphics system was used only for a short period of time before it was replaced by the more sophisticated ReGIS system, first introduced on the VT125 in 1981. ReGIS allowed the construction of arbitrary vectors and other shapes. Whereas DEC normally provided a backward compatible solution ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tektronix 4010
The Tektronix 4010 series was a family of text-and-graphics computer terminals based on storage-tube technology created by Tektronix. Several members of the family were introduced during the 1970s, the best known being the 11-inch 4010 and 19-inch 4014, along with the less popular 25-inch 4016. They were widely used in the computer-aided design market in the 1970s and early 1980s. The 4000 series were much less expensive than earlier graphics terminals, such as the IBM 2250, because no additional electronics were needed to maintain the display on the storage-tube screen; images drawn to the screen remained there until deliberately erased. This eliminated the need for computer memory to store the images, which was expensive in the 1970s. The display series remained popular until the introduction of inexpensive graphics workstations in the 1980s. These new graphics workstations used raster displays and dedicated screen buffers that became more affordable as solid-state memory c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polygraph
A polygraph, often incorrectly referred to as a lie detector test, is a pseudoscientific device or procedure that measures and records several physiological indicators such as blood pressure, pulse, respiration, and skin conductivity while a person is asked and answers a series of questions. The belief underpinning the use of the polygraph is that deceptive answers will produce physiological responses that can be differentiated from those associated with non-deceptive answers; however, there are no specific physiological reactions associated with lying, making it difficult to identify factors that separate those who are lying from those who are telling the truth. In some countries, polygraphs are used as an interrogation tool with criminal suspects or candidates for sensitive public or private sector employment. Some United States law enforcement and federal government agencies, as well as many police departments, use polygraph examinations to interrogate suspects and screen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sine Wave
A sine wave, sinusoidal wave, or sinusoid (symbol: ∿) is a periodic function, periodic wave whose waveform (shape) is the trigonometric function, trigonometric sine, sine function. In mechanics, as a linear motion over time, this is ''simple harmonic motion''; as rotation, it corresponds to ''uniform circular motion''. Sine waves occur often in physics, including wind waves, sound waves, and light waves, such as monochromatic radiation. In engineering, signal processing, and mathematics, Fourier analysis decomposes general functions into a sum of sine waves of various frequencies, relative phases, and magnitudes. When any two sine waves of the same frequency (but arbitrary phase (waves), phase) are linear combination, linearly combined, the result is another sine wave of the same frequency; this property is unique among periodic waves. Conversely, if some phase is chosen as a zero reference, a sine wave of arbitrary phase can be written as the linear combination of two sine wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASCII
ASCII ( ), an acronym for American Standard Code for Information Interchange, is a character encoding standard for representing a particular set of 95 (English language focused) printable character, printable and 33 control character, control characters a total of 128 code points. The set of available punctuation had significant impact on the syntax of computer languages and text markup. ASCII hugely influenced the design of character sets used by modern computers; for example, the first 128 code points of Unicode are the same as ASCII. ASCII encodes each code-point as a value from 0 to 127 storable as a seven-bit integer. Ninety-five code-points are printable, including digits ''0'' to ''9'', lowercase letters ''a'' to ''z'', uppercase letters ''A'' to ''Z'', and commonly used punctuation symbols. For example, the letter is represented as 105 (decimal). Also, ASCII specifies 33 non-printing control codes which originated with ; most of which are now obsolete. The control cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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), \\, and \134 (octal) all encode the same character: the ... [...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 interfa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BASIC Programming Language
Basic or BASIC may refer to: Science and technology * BASIC, a computer programming language * Basic (chemistry), having the properties of a base * Basic access authentication, in HTTP Entertainment * ''Basic'' (film), a 2003 film * Basic, one of the languages in ''Star Wars'' Music * ''Basic'' (Glen Campbell album), 1978 * ''Basic'' (Robert Quine and Fred Maher album), 1984 * ''B.A.S.I.C.'' (Alpinestars album), 2000 * ''Basic'' (Brown Eyed Girls album), 2015 * ''B.A.S.I.C.'' (The Basics album), 2019 Places * Basic, Mississippi, a community in the US * BASIC countries, Brazil, South Africa, India and China in climate change negotiations Organizations * BASIC Bank Limited, government owned bank in Bangladesh * Basic Books, an American publisher Other uses * Basic (cigarette), a brand of cigarettes manufactured by the Altria Group (Philip Morris Company) * Basic (dance move), the dance move that defines the character of a particular dance * Basic (slang), a pejorativ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DECwriter
The DECwriter series was a family of computer terminals from Digital Equipment Corporation (DEC). They were typically used in a fashion similar to a teletype, with a computer output being printed to paper and the user inputting information on the keyboard. In contrast to teletypes, the DECwriters were based on dot matrix printer technology, one of the first examples of such a system to be introduced. Versions lacking a keyboard were also available for use as computer printers, which eventually became the only models as Block-oriented terminal, smart terminals became the main way to interact with mainframes and minicomputers in the 1980s. There were four series of machines, starting with the original DECwriter in 1970, the DECwriter II in 1974, DECwriter III in 1978, and the final DECwriter IV in 1982. The first three were physically similar, large machines mounted on a stand normally positioned above a box of fanfold paper. They differed primarily in speed and the selection of com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PDP-11
The PDP–11 is a series of 16-bit minicomputers originally sold by Digital Equipment Corporation (DEC) from 1970 into the late 1990s, one of a set of products in the Programmed Data Processor (PDP) series. In total, around 600,000 PDP-11s of all models were sold, making it one of DEC's most successful product lines. The PDP-11 is considered by some experts to be the most popular minicomputer. The PDP–11 included a number of innovative features in its instruction set and additional general-purpose registers that made it easier to program than earlier models in the PDP series. Further, the innovative Unibus system allowed external devices to be more easily interfaced to the system using direct memory access, opening the system to a wide variety of peripherals. The PDP–11 replaced the PDP–8 in many real-time computing applications, although both product lines lived in parallel for more than 10 years. The ease of programming of the PDP–11 made it popular for general-pur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
