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Jiffy (time)
Jiffy can be an informal term for any unspecified short period, as in "I will be back in a jiffy". From this, it has acquired a number of more precise applications as the name of multiple units of measurement, each used to express or measure very brief durations of time. First attested in 1780, the word's origin is unclear, though one suggestion is that it was thieves' cant for lightning. It was common in a number of Scots English dialects and in John Jamieson's ''Etymological Dictionary of the Scottish Language'' (1808) it is suggested that it is a corruption of ' gliff' (glimpse) or 'gliffin' (glance) (compare: 'in the blink of an eye') and may ultimately derive from Gothic or Teutonic words for 'shine'. ('Gliff' or 'gliss' for 'a transient view' was also found in older English poetry as early as 1738.) Beginnings in measurement The earliest technical usage for jiffy was defined by Gilbert Newton Lewis (1875–1946). He proposed in 1926 a unit of time called the "jiffy" w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unit Of Time
A unit of time is any particular time interval, used as a standard way of measuring or expressing duration. The base unit of time in the International System of Units (SI), and by extension most of the Western world, is the second, defined as about 9 billion oscillations of the caesium atom. The exact modern SI definition is " he secondis defined by taking the fixed numerical value of the cesium frequency, , the unperturbed ground-state hyperfine transition frequency of the cesium 133 atom, to be when expressed in the unit Hz, which is equal to s−1." Historically, many units of time were defined by the movements of astronomical objects. * Sun-based: the year is based on the Earth's orbital period around the sun. Historical year-based units include the Olympiad (four years), the lustrum (five years), the indiction (15 years), the decade, the century, and the millennium. * Moon-based: the month is based on the Moon's orbital period around the Earth. * Earth-based: the da ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
System Time
In computer science and computer programming, system time represents a computer system's notion of the passage of time. In this sense, ''time'' also includes the passing of calendar date, days on the calendar. System time is measured by a ''system clock'', which is typically implemented as a simple count of the number of ''ticks'' that have transpired since some arbitrary starting date, called the ''epoch (computing), epoch''. For example, Unix and POSIX-compliant systems encode system time ("Unix time") as the number of seconds elapsed since the start of the Unix epoch at 1 January 1970 00:00:00 Universal Time, UT, with exceptions for leap seconds. Systems that implement the 32-bit and 64-bit versions of the Windows API, such as Windows 9x and Windows NT, provide the system time as both , represented as a year/month/day/hour/minute/second/milliseconds value, and , represented as a count of the number of 100-nanosecond ticks since 1 January 1601 00:00:00 UT as reckoned in the pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenwich Mean Time
Greenwich Mean Time (GMT) is the local mean time at the Royal Observatory, Greenwich, Royal Observatory in Greenwich, London, counted from midnight. At different times in the past, it has been calculated in different ways, including being calculated from noon; as a consequence, it cannot be used to specify a particular time unless a context is given. The term "GMT" is also used as Western European Time, one of the names for the time zone UTC+00:00 and, in UK law, is the basis for civil time in the United Kingdom. Because of Earth's uneven angular velocity in its Elliptic orbit, elliptical orbit and its axial tilt, noon (12:00:00) GMT is rarely the exact moment the Sun crosses the Prime meridian (Greenwich), Greenwich Meridian and reaches its highest point in the sky there. This event may occur up to 16 minutes before or after noon GMT, a discrepancy described by the equation of time. Noon GMT is the annual average (the arithmetic mean) moment of this event, which accounts f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratus VOS
Stratus VOS (Virtual Operating System) is a proprietary operating system running on Stratus Technologies fault-tolerant computer systems. VOS is available on Stratus's ftServer and Continuum platforms. VOS customers use it to support high-volume transaction processing applications which require continuous availability. VOS is notable for being one of the few operating systems which run on fully lockstepped hardware. During the 1980s, an IBM version of Stratus VOS existed and was called the System/88 Operating System. History VOS was designed from its inception as a high-security transaction-processing environment tailored to fault-tolerant hardware. It incorporates much of the design experience that came out of the MIT/Bell-Laboratories/General-Electric (later Honeywell) Multics project. In 1984, Stratus added a UNIX System V implementation called Unix System Facilities (USF) to VOS, integrating Unix and VOS at the kernel level. In recent years, Stratus has added POSIX-com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Jargon File
The Jargon File is a glossary and usage dictionary of slang used by computer programmers. The original Jargon File was a collection of terms from technical cultures such as the MIT AI Lab, the Stanford AI Lab (SAIL) and others of the old ARPANET AI/LISP/PDP-10 communities, including Bolt, Beranek and Newman (BBN), Carnegie Mellon University, and Worcester Polytechnic Institute. It was published in paperback form in 1983 as ''The Hacker's Dictionary'' (edited by Guy Steele) and revised in 1991 as ''The New Hacker's Dictionary'' (ed. Eric S. Raymond; third edition published 1996). The concept of the file began with the Tech Model Railroad Club (TMRC) that came out of early TX-0 and PDP-1 hackers in the 1950s, where the term ''hacker'' emerged and the ethic, philosophies and some of the nomenclature emerged. 1975 to 1983 The Jargon File (referred to here as "Jargon-1" or "the File") was made by Raphael Finkel at Stanford in 1975. From that time until the plug was finally pul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jargon File
The Jargon File is a glossary and usage dictionary of slang used by computer programmers. The original Jargon File was a collection of terms from technical cultures such as the MIT Computer Science and Artificial Intelligence Laboratory, MIT AI Lab, the Stanford University centers and institutes#Stanford Artificial Intelligence Laboratory, Stanford AI Lab (SAIL) and others of the old ARPANET Artificial intelligence, AI/Lisp programming language, LISP/PDP-10 communities, including BBN Technologies, Bolt, Beranek and Newman (BBN), Carnegie Mellon University, and Worcester Polytechnic Institute. It was published in paperback form in 1983 as ''The Hacker's Dictionary'' (edited by Guy L. Steele Jr., Guy Steele) and revised in 1991 as ''The New Hacker's Dictionary'' (ed. Eric S. Raymond; third edition published 1996). The concept of the file began with the Tech Model Railroad Club (TMRC) that came out of early TX-0 and PDP-1 hackers in the 1950s, where the term ''hacker'' emerged and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linux
Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, packaged as a Linux distribution (distro), which includes the kernel and supporting system software and library (computing), libraries—most of which are provided by third parties—to create a complete operating system, designed as a clone of Unix and released under the copyleft GPL license. List of Linux distributions, Thousands of Linux distributions exist, many based directly or indirectly on other distributions; popular Linux distributions include Debian, Fedora Linux, Linux Mint, Arch Linux, and Ubuntu, while commercial distributions include Red Hat Enterprise Linux, SUSE Linux Enterprise, and ChromeOS. Linux distributions are frequently used in server platforms. Many Linux distributions use the word "Linux" in their name, but the Free ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commodore 64
The Commodore 64, also known as the C64, is an 8-bit computing, 8-bit home computer introduced in January 1982 by Commodore International (first shown at the Consumer Electronics Show, January 7–10, 1982, in Las Vegas). It has been listed in the Guinness World Records as the highest-selling single computer model of all time, with independent estimates placing the number sold between 12.5 and 17 million units. Volume production started in early 1982, marketing in August for . Preceded by the VIC-20 and Commodore PET, the C64 took its name from its of RAM. With support for multicolor sprite (computer graphics), sprites and a custom chip for waveform generation, the C64 could create superior visuals and audio compared to systems without such custom hardware. The C64 dominated the low-end computer market (except in the UK, France and Japan, lasting only about six months in Japan) for most of the later years of the 1980s. For a substantial period (1983–1986), the C64 had betwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VIC-20
The VIC-20 (known as the VC-20 in Germany and the VIC-1001 in Japan) is an 8-bit entry level home computer that was sold by Commodore International, Commodore Business Machines. The VIC-20 was announced in 1980, roughly three years after Commodore's first personal computer, the Commodore PET, PET. The VIC-20 was the first computer of any description to sell one million units, eventually reaching 2.5 million. It was described as "one of the first anti-spectatorial, non-esoteric computers by design...no longer relegated to hobbyist/enthusiasts or those with money, the computer Commodore developed was the computer of the future." History As the Apple II gained momentum with the advent of VisiCalc in 1979, Jack Tramiel wanted a product that would compete in the same segment, to be presented at the January 1980 Consumer Electronics Show, CES. For this reason Chuck Peddle and Bill Seiler started to design a computer named ''TOI'' (The Other Intellect). The TOI computer failed to m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commodore PET
The Commodore PET is a line of personal computers produced starting in 1977 by Commodore International. A single all-in-one case combines a MOS Technology 6502 microprocessor, Commodore BASIC in read-only memory, keyboard, monochrome monitor, and, in early models, a cassette deck. Development of the system began in 1976, and it was demonstrated and sold as the first personal computer for the masses at the January 1977 Consumer Electronics Show. The name "PET" was suggested by Andre Souson after he saw the Pet Rock in Los Gatos, and stated they were going to make the "pet computer". It was backronymed to Personal Electronic Transactor. In a 1995 retrospective, ''Byte'' magazine—and subsequently many others—referred to the PET, Apple II and TRS-80 collectively as the "1977 trinity" of pioneering personal computers. Following the initial PET 2001, the design was updated through a series of models with more memory, better keyboard, larger screen, and other modifications. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NTSC
NTSC (from National Television System Committee) is the first American standard for analog television, published and adopted in 1941. In 1961, it was assigned the designation System M. It is also known as EIA standard 170. In 1953, a second NTSC standard was adopted, which allowed for color television broadcast compatible with the existing stock of black-and-white receivers. It is one of three major color formats for analog television, the others being PAL and SECAM. ''NTSC color'' is usually associated with the System M; this combination is sometimes called NTSC II. The only other broadcast television system to use NTSC color was the System J. Brazil used System M with PAL color. Vietnam, Cambodia and Laos used System M with SECAM color – Vietnam later started using PAL in the early 1990s. The NTSC/System M standard was used in most of the Americas (except Argentina, Brazil, Paraguay, and Uruguay), Myanmar, South Korea, Taiwan, Philippines, Japan, and some Pacific Isl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hertz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or Cycle per second, cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base units is 1/s or s−1, meaning that one hertz is one per second or the Inverse second, reciprocal of one second. It is used only in the case of periodic events. It is named after Heinrich Hertz, Heinrich Rudolf Hertz (1857–1894), the first person to provide conclusive proof of the existence of electromagnetic waves. For high frequencies, the unit is commonly expressed in metric prefix, multiples: kilohertz (kHz), megahertz (MHz), gigahertz (GHz), terahertz (THz). Some of the unit's most common uses are in the description of periodic waveforms and musical tones, particularly those used in radio- and audio-related applications. It is also used to describe the clock speeds at which computers and other electronics are driven. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
