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Rack Units
A rack unit (abbreviated U or RU) is a unit of measure defined as . It is most frequently used as a measurement of the overall height of 19-inch and 23-inch rack frames, as well as the height of equipment that mounts in these frames, whereby the height of the frame or equipment is expressed as multiples of rack units. For example, a typical full-size rack cage is 42U high, while equipment is typically 1U, 2U, 3U, or 4U high. Definition The rack unit size is based on a standard rack specification as defined in EIA-310. The Eurocard specifies a standard rack unit as the unit of height; it also defines a similar unit, horizontal pitch (HP), used to measure the width of rack-mounted equipment. The standard was adopted worldwide as ''IEC 60297 Mechanical structures for electronic equipment – Dimensions of mechanical structures of the series'', and defines the sizes for rack, subrack (a shelf-like chassis in which cards can be inserted), and the pitch of printed circuit boards/ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Router (computing)
A router is a networking device that forwards data packets between computer networks. Routers perform the traffic directing functions between networks and on the global Internet. Data sent through a network, such as a web page or email, is in the form of data packets. A packet is typically forwarded from one router to another router through the networks that constitute an internetwork (e.g. the Internet) until it reaches its destination node. A router is connected to two or more data lines from different IP networks. When a data packet comes in on one of the lines, the router reads the network address information in the packet header to determine the ultimate destination. Then, using information in its routing table or routing policy, it directs the packet to the next network on its journey. The most familiar type of IP routers are home and small office routers that simply forward IP packets between the home computers and the Internet. More sophisticated routers, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanical Standards
Mechanical may refer to: Machine * Machine (mechanical), a system of mechanisms that shape the actuator input to achieve a specific application of output forces and movement * Mechanical calculator, a device used to perform the basic operations of arithmetic * Mechanical energy, the sum of potential energy and kinetic energy * Mechanical system, a system that manages the power of forces and movements to accomplish a task * Mechanism (engineering), a portion of a mechanical device Other * Mechanical (character), one of several characters in Shakespeare's ''A Midsummer Night's Dream'' * A kind of typeface in the VOX-ATypI classification See also * Machine, especially in opposition to an electronic item * ''Mechanical Animals'', the third full-length studio release by Marilyn Manson * Manufactured or artificial, especially in opposition to a biological or natural component * Automation, using machine decisions and processing instead of human * Mechanization, using machine labor inste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Units Of Length
A unit of length refers to any arbitrarily chosen and accepted reference standard for measurement of length. The most common units in modern use are the metric units, used in every country globally. In the United States the U.S. customary units are also in use. British Imperial units are still used for some purposes in the United Kingdom and some other countries. The metric system is sub-divided into SI and non-SI units. Metric system SI The base unit in the International System of Units (SI) is the metre, defined as "the length of the path travelled by light in vacuum during a time interval of seconds." It is approximately equal to . Other SI units are derived from the metre by adding prefixes, as in millimetre or kilometre, thus producing systematic decimal multiples and submultiples of the base unit that span many orders of magnitude. For example, a kilometre is . Non-SI In the centimetre–gram–second system of units, the basic unit of length is the centimetre, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Unusual Units Of Measurement
An unusual unit of measurement is a unit of measurement that does not form part of a coherent system of measurement, especially because its exact quantity may not be well known or because it may be an inconvenient multiple or fraction of a base unit. This definition is not exact since it includes units such as the ''week'' or the '' light-year'', which are quite "usual" in the sense that they are often used, but can be "unusual" if taken out of their common context, as demonstrated by the furlong-firkin-fortnight (FFF) system of units. Many of the unusual units of measurements listed here are colloquial measurements, units devised to compare a measurement to common and familiar objects. Length Hammer unit Valve's Source game engine uses the ''Hammer unit'' as its base unit of length. This unit refers to Source's official map creation software, Hammer. The exact definition varies from game to game, but a Hammer unit is usually defined as a sixteenth of a foot (16 Ham ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enclosure (electrical)
An electrical enclosure is a cabinet for electrical or electronic equipment to mount switches, knobs and displays and to prevent electrical shock to equipment users and protect the contents from the environment. The enclosure is the only part of the equipment which is seen by users. It may be designed not only for its utilitarian requirements, but also to be pleasing to the eye. Regulations may dictate the features and performance of enclosures for electrical equipment in hazardous areas, such as petrochemical plants or coal mines. Electronic packaging may place many demands on an enclosure for heat dissipation, radio frequency interference and electrostatic discharge protection, as well as functional, esthetic and commercial constraints. Standards Internationally, IEC 60529 classifies the ingress protection rating (IP Codes) of enclosures. In the United States, the National Electrical Manufacturers Association (NEMA) publishes NEMA enclosure type standards for the performa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cage Nut
A cage nut or caged nut (also called a captive or clip nut) consists of a (usually square) nut in a spring steel cage which wraps around the nut. The cage has two wings that when compressed allow the cage to be inserted into the square holes, for example, in the mounting rails of equipment racks. When the wings are released, they hold the nut in position behind the hole. Cage nuts conforming to this description were patented in 1952 and 1953. This design requires insertion tools to install the cage nut into the hole. Newer designs featuring a squeeze-and-release tab allow for tool-less installation. The square-hole cage nut can be used wherever a square hole can be punched. An older type of captive-nut uses a spring clip that holds the nut and slides on the edge of a thin sheet. While this type of cage nut can only position the nut a fixed distance from the edge of a thin plate, it works equally well with square and round holes. A patent for such a nut was granted in 1946.George A. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unified Thread Standard
The Unified Thread Standard (UTS) defines a standard thread form and series—along with allowances, tolerances, and designations—for screw threads commonly used in the United States and Canada. It is the main standard for bolts, nuts, and a wide variety of other threaded fasteners used in these countries. It has the same 60° profile as the ISO metric screw thread, but the characteristic dimensions of each UTS thread (outer diameter and pitch) were chosen as an inch fraction rather than a millimeter value. The UTS is currently controlled by ASME/ANSI in the United States. Origins : ''See the "History of standardization" section of the screw thread article.'' Basic profile Each thread in the series is characterized by its major diameter ''D''maj and its pitch, ''P''. UTS threads consist of a symmetric V-shaped thread. In the plane of the thread axis, the flanks of the V have an angle of 60° to each other. The outermost and the innermost of the height ''H'' of the V-sha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Server (computing)
In computing, a server is a piece of computer hardware or software (computer program) that provides functionality for other programs or devices, called " clients". This architecture is called the client–server model. Servers can provide various functionalities, often called "services", such as sharing data or resources among multiple clients, or performing computation for a client. A single server can serve multiple clients, and a single client can use multiple servers. A client process may run on the same device or may connect over a network to a server on a different device. Typical servers are database servers, file servers, mail servers, print servers, web servers, game servers, and application servers. Client–server systems are usually most frequently implemented by (and often identified with) the request–response model: a client sends a request to the server, which performs some action and sends a response back to the client, typically with a result or acknowledg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KVM Switch
A KVM switch (with KVM being an abbreviation for "keyboard, video, and mouse") is a hardware device that allows a user to control multiple computers from one or more sets of keyboards, video monitors, and mice. Name Switches to connect multiple computers to one or more peripherals have had a variety of names. The earliest name was Keyboard Video Switch (KVS). With the advent of the mouse, the Keyboard, Video and Mouse (KVM) switch became popular. The name was introduced by Remigius Shatas, the founder of Cybex, a peripheral switch manufacturer, in 1995. Some companies call their switches Keyboard, Video, Mouse and Peripheral (KVMP). Types With the popularity of USB—USB keyboards, mice, and I/O devices are still the most common devices connected to a KVM switch. The classes of KVM switches that are reviewed, are based on different types of core technologies in terms of how the KVM switch handles USB I/O devices—including keyboards, mice, touchscreen displays, etc. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Switch
A network switch (also called switching hub, bridging hub, and, by the IEEE, MAC bridge) is networking hardware that connects devices on a computer network by using packet switching to receive and forward data to the destination device. A network switch is a multiport network bridge that uses MAC addresses to forward data at the data link layer (layer 2) of the OSI model. Some switches can also forward data at the network layer (layer 3) by additionally incorporating routing functionality. Such switches are commonly known as layer-3 switches or multilayer switches. Switches for Ethernet are the most common form of network switch. The first MAC Bridge was invented in 1983 by Mark Kempf, an engineer in the Networking Advanced Development group of Digital Equipment Corporation. The first 2 port Bridge product (LANBridge 100) was introduced by that company shortly after. The company subsequently produced multi-port switches for both Ethernet and FDDI such as GigaSwitch. Digital ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Server Rack Rail Dimensions
Server may refer to: Computing *Server (computing), a computer program or a device that provides functionality for other programs or devices, called clients Role * Waiting staff, those who work at a restaurant or a bar attending customers and supplying them with food and drink as requested * Server, a tennis player who makes a serve; see Serve (tennis) * Altar server, a lay assistant to a member of the clergy during a Christian liturgy. Other uses * Server (name) * ''Server Sundaram'', a 1964 Indian comedy film * Server, any serving utensil; see List of serving utensils See also * Serve (other) * Service (other) Service may refer to: Activities * Administrative service, a required part of the workload of university faculty * Civil service, the body of employees of a government * Community service, volunteer service for the benefit of a community or a p ... * Cake and pie server * * {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
