An embedded system is a computer system A computer is a machine that manipulates data according to a set of instructions designed to perform one or a few dedicated functions[1][2] often with real-time computing In computer science, real-time computing , or "reactive computing", is the study of hardware and software systems that are subject to a "real-time constraint"—i.e., operational deadlines from event to system response. By contrast, a non-real-time system is one for which there is no deadline, even if fast response or high constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal computer A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end user, with no intervening computer operator. This is in contrast to the batch processing or time-sharing models which allowed large expensive mainframe, is designed to be flexible and to meet a wide range of end-user needs. Embedded systems control many devices in common use today.[3]
Embedded systems are controlled by one or more main processing cores that is typically either a microcontroller A microcontroller is a small computer on a single integrated circuit consisting internally of a relatively simple CPU, clock, timers, I/O ports, and memory. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM. Microcontrollers are designed for small or dedicated applications or a digital signal processor A digital signal processor is a specialized microprocessor with optimized architecture for fast operational needs of Digital Signal Processing (DSP).[4] The key characteristic is however being dedicated to handle a particular task, which may require very powerful processors. For example, air traffic control Air traffic control is a service provided by ground-based controllers who direct aircraft on the ground and in the air. The primary purpose of ATC systems worldwide is to separate aircraft to prevent collisions, to organize and expedite the flow of traffic, and to provide information and other support for pilots when able. In some countries, ATC systems may usefully be viewed as embedded, even though they involve mainframe computers and dedicated regional and national networks between airports and radar sites. (Each radar probably includes one or more embedded systems of its own.)
Since the embedded system is dedicated to specific tasks, design engineers can optimize it reducing the size and cost of the product and increasing the reliability and performance. Some embedded systems are mass-produced, benefiting from economies of scale Economies of scale, in microeconomics, are the cost advantages that a business obtains due to expansion. They are factors that cause a producer’s average cost per unit to fall as scale is increased. Economies of scale is a long run concept and refers to reductions in unit cost as the size of a facility, or scale, increases. Diseconomies of scale.
Physically, embedded systems range from portable devices such as digital watches A watch is a timepiece that is made to be worn on a person. It is usually a wristwatch, worn on the wrist with a strap or bracelet. In addition to the time, modern watches often display the day, date, month and year, and electronic watches may have many other functions and MP3 players A digital audio player, usually referred to as an MP3 player, is a consumer electronic device that has the primary function of storing, organizing and playing audio files. Some DAPs are also referred to as portable media players as they have image-viewing and/or video-playing support, to large stationary installations like traffic lights Traffic lights, which may also be known as stoplights, traffic lamps, traffic signals, stop-and-go lights, robots or semaphore, are signaling devices positioned at road intersections, pedestrian crossings and other locations to control competing flows of traffic. Traffic lights have been installed in most cities around the world. They assign the, factory controllers A programmable logic controller or programmable controller is a digital computer used for automation of electromechanical processes,such as control of machinery on factory assembly lines, amusement rides, or lighting fixtures. PLCs are used in many industries and machines. Unlike general-purpose computers, the PLC is designed for multiple inputs, or the systems controlling nuclear power plants Nuclear power is power produced from controlled (i.e., non-explosive) nuclear reactions. Commercial plants in use to date use nuclear fission reactions. Electric utility reactors heat water to produce steam, which is then used to generate electricity. In 2007, 14% of the world's electricity came from nuclear power, despite concerns about safety. Complexity varies from low, with a single microcontroller A microcontroller is a small computer on a single integrated circuit consisting internally of a relatively simple CPU, clock, timers, I/O ports, and memory. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM. Microcontrollers are designed for small or dedicated applications chip, to very high with multiple units, peripherals and networks mounted inside a large chassis A chassis (pronounced /ˈʃæsi, ˈtʃæsi/) consists of a framework that supports a man-made object, analogous to an animal's skeleton, for example in a motor vehicle or a firearm or enclosure.
In general, "embedded system" is not a strictly definable term, as most systems have some element of extensibility or programmability. For example, handheld computers A mobile device is a pocket-sized computing device, typically having a display screen with touch input or a miniature keyboard. In the case of the personal digital assistant (PDA) the input and output are combined into a touch-screen interface. Smartphones and PDAs are popular amongst those who require the assistance and convenience of a share some elements with embedded systems such as the operating systems and microprocessors which power them, but they allow different applications to be loaded and peripherals to be connected. Moreover, even systems which don't expose programmability as a primary feature generally need to support software updates. On a continuum from "general purpose" to "embedded", large application systems will have subcomponents at most points even if the system as a whole is "designed to perform one or a few dedicated functions", and is thus appropriate to call "embedded".
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outside the main building State of the art ground transportation is available to attendees in San Jose Seriously this one looks like lots of fun especially in todays warm weather Overflow exhibits in the hallway of the convention center In earlier shows this was a quiet place to relax between exhibits and conference sessions Thursday September 30 1999 Building
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Is "embedded" getting to be a meaningless label like minicomputer? One problem is that even we don't always agree on what makes an . embedded system. . I spent most of my career working on what I think of as highly . embedded systems. . ...
