Misplaced Pages

#45954

42-515: [REDACTED] Look up Ctrl in Wiktionary, the free dictionary. CTRL or Ctrl may refer to several things: Channel Tunnel Rail Link or High Speed 1 (HS1), a high-speed railway line linking London with the Channel Tunnel Control key , an input button present on most computer keyboards CTRL (gene) , a gene that in humans encodes

84-409: A byte or word , is referred to, it is usually specified by a number from 0 upwards corresponding to its position within the byte or word. However, 0 can refer to either the most or least significant bit depending on the context. Similar to torque and energy in physics; information-theoretic information and data storage size have the same dimensionality of units of measurement , but there

126-502: A unit of information , the bit is also known as a shannon , named after Claude E. Shannon . The symbol for the binary digit is either "bit", per the IEC 80000-13 :2008 standard, or the lowercase character "b", per the IEEE 1541-2002 standard. Use of the latter may create confusion with the capital "B" which is the international standard symbol for the byte. The encoding of data by discrete bits

168-482: A Bell Labs memo on 9 January 1947 in which he contracted "binary information digit" to simply "bit". A bit can be stored by a digital device or other physical system that exists in either of two possible distinct states . These may be the two stable states of a flip-flop , two positions of an electrical switch , two distinct voltage or current levels allowed by a circuit , two distinct levels of light intensity , two directions of magnetization or polarization ,

210-429: A bit was represented by the polarity of magnetization of a certain area of a ferromagnetic film, or by a change in polarity from one direction to the other. The same principle was later used in the magnetic bubble memory developed in the 1980s, and is still found in various magnetic strip items such as metro tickets and some credit cards . In modern semiconductor memory , such as dynamic random-access memory ,

252-457: A facility of Cyberoam The stock symbol for Control4 See also [ edit ] Control-Alt-Delete (disambiguation) CNTRL , protein that in humans is encoded by the CNTRL gene CNTRL: Beyond EDM , a North American educational initiative, centered on electronic dance music Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with

294-404: A time in serial transmission , and by a multiple number of bits in parallel transmission . A bitwise operation optionally processes bits one at a time. Data transfer rates are usually measured in decimal SI multiples of the unit bit per second (bit/s), such as kbit/s. In the earliest non-electronic information processing devices, such as Jacquard's loom or Babbage's Analytical Engine , a bit

336-486: Is in general no meaning to adding, subtracting or otherwise combining the units mathematically, although one may act as a bound on the other. Units of information used in information theory include the shannon (Sh), the natural unit of information (nat) and the hartley (Hart). One shannon is the maximum amount of information needed to specify the state of one bit of storage. These are related by 1 Sh ≈ 0.693 nat ≈ 0.301 Hart. Some authors also define

378-554: Is more compressed—the same bucket can hold more. For example, it is estimated that the combined technological capacity of the world to store information provides 1,300 exabytes of hardware digits. However, when this storage space is filled and the corresponding content is optimally compressed, this only represents 295 exabytes of information. When optimally compressed, the resulting carrying capacity approaches Shannon information or information entropy . Certain bitwise computer processor instructions (such as bit set ) operate at

420-592: Is usually labeled Ctrl ( Control or Ctl are sometimes used, but it is uncommon). Abbreviations in the language of the keyboard layout also are in use, e.g., the German keyboard layout uses Strg as required by the German standard DIN 2137:2012-06. There is a standardized keyboard symbol (to be used when Latin lettering is not preferred). This symbol is encoded in Unicode as U+2388 helm symbol ⎈ , but it

462-461: Is very rarely used. On teletypewriters and computer terminals , holding down the Control key while pressing another key would send an ASCII C0 control character , instead of directly reporting a key press to the system. The control characters were used as non-printing characters that signal the terminal or teletypewriter to perform a special action, such as ringing a bell, ejecting a page or erasing

SECTION 10

#1732845093046

504-596: The IBM PC , positioned the Control key on the left of the keyboard, whereas caps lock resides in the same position on most modern keyboards. The traditional layout was preserved for later workstation systems and is often associated with Unix workstations. Keyboards from Sun Microsystems came in two layouts; "Unix" and "PC-style", with the Unix layout having the traditional placing of the Control key and other keys. The keyboards produced for One Laptop Per Child computers also have

546-410: The yottabit (Ybit). When the information capacity of a storage system or a communication channel is presented in bits or bits per second , this often refers to binary digits, which is a computer hardware capacity to store binary data ( 0 or 1 , up or down, current or not, etc.). Information capacity of a storage system is only an upper bound to the quantity of information stored therein. If

588-449: The 1940s, computer builders experimented with a variety of storage methods, such as pressure pulses traveling down a mercury delay line , charges stored on the inside surface of a cathode-ray tube , or opaque spots printed on glass discs by photolithographic techniques. In the 1950s and 1960s, these methods were largely supplanted by magnetic storage devices such as magnetic-core memory , magnetic tapes , drums , and disks , where

630-567: The Control key in this location. Other vendors produce keyboards for different computer systems with this placement of the Control key, such as the Happy Hacking Keyboard . Some users of keyboards with caps lock on the left remap the keys to exchange Control and caps lock, finding the traditional location more ergonomic for using programs benefiting from use of the Control key. Keyboard layout preferences specifically to address this need are available in some operating systems. Others leave

672-597: The Control key is used to invoke a "right-click". Apple calls this a "secondary click" as left-handers can choose which side this button is on. Bit The bit is the most basic unit of information in computing and digital communication . The name is a portmanteau of binary digit . The bit represents a logical state with one of two possible values . These values are most commonly represented as either " 1 " or " 0 " , but other representations such as true / false , yes / no , on / off , or + / − are also widely used. The relation between these values and

714-409: The ambiguity of relying on the underlying hardware design, the unit octet was defined to explicitly denote a sequence of eight bits. Computers usually manipulate bits in groups of a fixed size, conventionally named " words ". Like the byte, the number of bits in a word also varies with the hardware design, and is typically between 8 and 80 bits, or even more in some specialized computers. In

756-424: The average. This principle is the basis of data compression technology. Using an analogy, the hardware binary digits refer to the amount of storage space available (like the number of buckets available to store things), and the information content the filling, which comes in different levels of granularity (fine or coarse, that is, compressed or uncompressed information). When the granularity is finer—when information

798-512: The character "a" has a binary ASCII code of 110 0001 . This code would be converted to 000 0001 , corresponding to the ASCII character with id 1 (the SOH Character). The table at C0 and C1 control codes § C0 controls shows the ASCII control characters, with the " Caret notation " column showing a caret (^), followed by the character to press while the Control key is held down to generate

840-422: The character. If a teletypewriter or terminal is connected to a computer, the software on the computer can interpret control characters it receives however it is written to do so; a given control character can be interpreted differently from how it would be interpreted by a teletypewriter or terminal that receives it. For example, Control-C , received from a teletypewriter or terminal, is interpreted as "interrupt

882-462: The control key in the lower-left corner of the keyboard, and press it using the side of their palm. The choice of location for the control key often comes down to the typist's hand shape and posture. There are several common notations for pressing the Control key in conjunction with another key. Each notation below means press and hold Ctrl while pressing the X key: Different application programs, user interfaces, and operating systems use

SECTION 20

#1732845093046

924-452: The current program" in some command-line interfaces , and Control-E is interpreted by the Emacs text editor as "move the editor cursor to the end of the line". Computer keyboards directly attached to a computer, as is the case for a personal computer or workstation , distinguish each physical key from every other and report all keypresses and releases to the controlling software. This allows

966-415: The early 21st century, retail personal or server computers have a word size of 32 or 64 bits. The International System of Units defines a series of decimal prefixes for multiples of standardized units which are commonly also used with the bit and the byte. The prefixes kilo (10 ) through yotta (10 ) increment by multiples of one thousand, and the corresponding units are the kilobit (kbit) through

1008-407: The enzyme chymotrypsin-like protease CTRL-1 Ctrl (web series) , an American comedy web series from NBC Ctrl (Derek Webb album) , a 2012 album by singer-songwriter Derek Webb Ctrl (SZA album) , a 2017 album by singer-songwriter SZA CTRL (TV series) , a 2021 Singaporean television drama CTRL (film) , a 2024 Indian thriller film from Netflix Cyberoam Threat Research Labs ,

1050-409: The level of manipulating bits rather than manipulating data interpreted as an aggregate of bits. In the 1980s, when bitmapped computer displays became popular, some computers provided specialized bit block transfer instructions to set or copy the bits that corresponded to a given rectangular area on the screen. In most computers and programming languages, when a bit within a group of bits, such as

1092-408: The orientation of reversible double stranded DNA , etc. Bits can be implemented in several forms. In most modern computing devices, a bit is usually represented by an electrical voltage or current pulse, or by the electrical state of a flip-flop circuit. For devices using positive logic , a digit value of 1 (or a logical value of true) is represented by a more positive voltage relative to

1134-443: The physical states of the underlying storage or device is a matter of convention, and different assignments may be used even within the same device or program . It may be physically implemented with a two-state device. A contiguous group of binary digits is commonly called a bit string , a bit vector, or a single-dimensional (or multi-dimensional) bit array . A group of eight bits is called one  byte , but historically

1176-517: The representation of 0 . Different logic families require different voltages, and variations are allowed to account for component aging and noise immunity. For example, in transistor–transistor logic (TTL) and compatible circuits, digit values 0 and 1 at the output of a device are represented by no higher than 0.4 V and no lower than 2.6 V, respectively; while TTL inputs are specified to recognize 0.8 V or below as 0 and 2.2 V or above as 1 . Bits are transmitted one at

1218-425: The same holds for saving, cutting, and pasting). Macintoshes also have a Control key, but it has different functionality. The original Apple mouse design reduced complexity by only offering one button. As the interface developed, contextual menus were offered to access extra options. Another button was needed to access these. On Unix and Windows, the user had other mouse buttons to use. On Classic Mac OS and macOS,

1260-426: The screen, or controlling where the next character will display. The first 32 ASCII characters are the control characters, representable by a 5- bit binary number. Because ASCII characters were represented as 7 bits, if a key is pressed while the Control key was held down, teletypewriters and terminals would simply set the first 2 bits of a character to 0, converting the character into a control character. For example,

1302-424: The size of the byte is not strictly defined. Frequently, half, full, double and quadruple words consist of a number of bytes which is a low power of two. A string of four bits is usually a nibble . In information theory , one bit is the information entropy of a random binary variable that is 0 or 1 with equal probability, or the information that is gained when the value of such a variable becomes known. As

CTRL - Misplaced Pages Continue

1344-531: The software to interpret Control key combinations as it chooses, including being able to interpret a combination of the Control key, another modifier key , and a letter, number, or symbol key differently from the way it interprets a combination of the Control key and the letter, number, or symbol key without that other modifier key. The keyboards of many early computer terminals , including the Teletype Model 33 ASR and Lear-Siegler ADM-3A , and early models of

1386-552: The thickness of alternating black and white lines. The bit is not defined in the International System of Units (SI). However, the International Electrotechnical Commission issued standard IEC 60027 , which specifies that the symbol for binary digit should be 'bit', and this should be used in all multiples, such as 'kbit', for kilobit. However, the lower-case letter 'b' is widely used as well and

1428-496: The title CTRL . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=CTRL&oldid=1254690347 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Ctrl On keyboards that use English abbreviations for key labeling, it

1470-556: The two possible values of one bit of storage are not equally likely, that bit of storage contains less than one bit of information. If the value is completely predictable, then the reading of that value provides no information at all (zero entropic bits, because no resolution of uncertainty occurs and therefore no information is available). If a computer file that uses n  bits of storage contains only m  <  n  bits of information, then that information can in principle be encoded in about m  bits, at least on

1512-444: The two values of a bit may be represented by two levels of electric charge stored in a capacitor . In certain types of programmable logic arrays and read-only memory , a bit may be represented by the presence or absence of a conducting path at a certain point of a circuit. In optical discs , a bit is encoded as the presence or absence of a microscopic pit on a reflective surface. In one-dimensional bar codes , bits are encoded as

1554-554: The various control key combinations for different purposes. In early first-person shooters , the left Ctrl key is often used to fire a weapon. In newer games, the key is often used for crouching instead. Generally, the Command key , labeled with the ⌘ symbol on Apple Macintosh computers, performs the equivalent functions in classic Mac OS and macOS applications (for example, ⌘C copies, while ⌘P prints;

1596-447: Was also used in Morse code (1844) and early digital communications machines such as teletypes and stock ticker machines (1870). Ralph Hartley suggested the use of a logarithmic measure of information in 1928. Claude E. Shannon first used the word "bit" in his seminal 1948 paper " A Mathematical Theory of Communication ". He attributed its origin to John W. Tukey , who had written

1638-460: Was often stored as the position of a mechanical lever or gear, or the presence or absence of a hole at a specific point of a paper card or tape . The first electrical devices for discrete logic (such as elevator and traffic light control circuits , telephone switches , and Konrad Zuse's computer) represented bits as the states of electrical relays which could be either "open" or "closed". When relays were replaced by vacuum tubes , starting in

1680-503: Was recommended by the IEEE 1541 Standard (2002) . In contrast, the upper case letter 'B' is the standard and customary symbol for byte. Multiple bits may be expressed and represented in several ways. For convenience of representing commonly reoccurring groups of bits in information technology, several units of information have traditionally been used. The most common is the unit byte , coined by Werner Buchholz in June 1956, which historically

1722-541: Was used in the punched cards invented by Basile Bouchon and Jean-Baptiste Falcon (1732), developed by Joseph Marie Jacquard (1804), and later adopted by Semyon Korsakov , Charles Babbage , Herman Hollerith , and early computer manufacturers like IBM . A variant of that idea was the perforated paper tape . In all those systems, the medium (card or tape) conceptually carried an array of hole positions; each position could be either punched through or not, thus carrying one bit of information. The encoding of text by bits

CTRL - Misplaced Pages Continue

1764-405: Was used to represent the group of bits used to encode a single character of text (until UTF-8 multibyte encoding took over) in a computer and for this reason it was used as the basic addressable element in many computer architectures . The trend in hardware design converged on the most common implementation of using eight bits per byte, as it is widely used today. However, because of

#45954