Dedicated computers are special purpose machines. They include video game units like Play stations and X-Box. Video game units come in a range of sizes. The smallest are handheld, battery-operated toys.
A larger unit for home use sits on the floor or a table and can be connected to a television set. A player generally controls a home unit through a joystick, which may include a trigger and one or more buttons. The largest units stand on the floor in arcades and in other commercial establishments.
A larger unit for home use sits on the floor or a table and can be connected to a television set. A player generally controls a home unit through a joystick, which may include a trigger and one or more buttons. The largest units stand on the floor in arcades and in other commercial establishments.
Embedded computers are control units built into the devices they control. Virtually all embedded computers are single micro-processors. Such devices as digital wristwatches, telephones, washing machines, microwaves and automobile ignition systems contain embedded computers.In addition, embedded computers help control the flight of aircraft, maintain the orbits of artificial satellites, and guide missiles to their targets. They also control the movements of industrial robots.
Properties :
1. Embedded systems are designed to do some specific task, rather than be a general-purpose computer for multiple tasks. Some also have real-time performance constraints that must be met, for reasons such as safety and usability; others may have low or no performance requirements, allowing the system hardware to be simplified to reduce costs.
2. Embedded systems are not always standalone devices. Many embedded systems consist of small, computerized parts within a larger device that serves a more general purpose.
Example (taken from wikipedia) : the Gibson Robot Guitar features an embedded system for tuning the strings, but the overall purpose of the Robot Guitar is, of course, to play music. Similarly, an embedded system in an automobile provides a specific function as a subsystem of the car itself.
3. The program instructions written for embedded systems are referred to as firmware, and are stored in read-only memory or Flash memory chips. They run with limited computer hardware resources: little memory, small or non-existent keyboard or screen.
Interesting Facts :
First recognizably modern embedded systems was the Apollo Guidance Computer, developed by Charles Stark Draper at the MIT Instrumentation Laboratory.
The Apollo guidance computer was considered the riskiest item in the Apollo project as it employed the then newly developed monolithic integrated circuits to reduce the size and weight.
An early mass-produced embedded system was the Autonetics D-17 guidance computer for the Minuteman missile, released in 1961. It was built from transistor logic and had a hard disk for main memory. When the Minuteman II went into production in 1966,
D-17 was replaced with a new computer that was the first high-volume use of integrated circuits. This program alone reduced prices on quad nand gate ICs from $1000/each to $3/each, permitting their use in commercial products.
Since these early applications in the 1960s, embedded systems have come down in price and there has been a dramatic rise in processing power and functionality.
The first microprocessor for example, the Intel 4004, was designed for calculators and other small systems but still required many external memory and support chips.
In 1978 National Engineering Manufacturers Association released a "standard" for programmable microcontrollers, including almost any computer-based controllers, such as single board computers, numerical, and event-based controllers.