1.1 EMBEDDED SYSTEM:
An embedded system is a special-purpose system in which the computer is completely encapsulated by or dedicated to the device or system it controls. Unlike a general-purpose computer, such as a personal computer, an embedded system performs one or a few predefined tasks, usually with very specific requirements. Since the system is dedicated to specific tasks, design engineers can optimize it, reducing the size and cost of the product. Embedded systems are often mass-produced, benefiting from economies of scale.
Personal digital assistants (PDAs) or handheld computers are generally considered embedded devices because of the nature of their hardware design, even though they are more expandable in software terms. This line of definition continues to blur as devices expand. With the introduction of the OQO Model 2 with the Windows XP operating system and ports such as a USB port
both features usually Belong to "general purpose computers", — the line of nomenclature blurs even more.
Physically, embedded systems ranges from portable devices such as digital watches and MP3 players, to large stationary installations like traffic lights, factory controllers, or the systems controlling nuclear power plants.
In terms of complexity embedded systems can range from very simple with a single microcontroller chip, to very complex with multiple units, peripherals and networks mounted inside a large chassis or enclosure.
In the 1960s, computers possessed an ability to acquire, analyze, process data, and make decisions at very high speeds. However there were some disadvantages with the computer controls. They were: high cost, program complexity, and hesitancy of personnel to learn. However the new concept of electronic devices was evolved. They were called programmable controllers which later became a part of embedded systems. This concept developed from a mix of computer technology, solid state devices, and
References: on the Web: www.national.com www.atmel.com www.microsoftsearch.com www.geocities.com