A special purpose computer is one designed to solve only a narrow range of problems. These are often simpler and cheaper than general purpose computers. They also tend to have limited logical and computational capabilities. The computing resources are often chosen so as to just be enough to meet the demands of the tasks that they have to perform.
As more devices, gadgets and appliances are getting “smarter” every day, the number of what could be classified as special purpose computers also rises. Some of these devices serve critical purposes while others exist for the mere convenience of the end user. Here are some examples of special purpose computers and their uses.
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In domestic appliances
Several domestic appliances are examples of special purpose computers. Household gadgets like washing machines and microwave ovens often contain microcontrollers (basically small computers the size of microchips) to facilitate functions like timing and the automatic control of these devices. As an example, many washing machines can sense the weight of the laundry placed inside them and are then able to optimise their operation based on this information. Household gadgets like DVD players, CD players and televisions also contain these embedded computers.
Modern smartphones are for the most part general purpose computers; however their predecessors, the so-called feature or dumb phones (many of which are still in use even nowadays) are specialized computing devices. Their processing functions are limited to activities such as making or receiving calls, sending and receiving text messages, and storing contact information.
Gaming consoles from a few years ago
While present day gaming consoles are becoming more of general purpose computing devices because of their increasing amount of functionality, their predecessors from only a few years ago were specialized for playing video games and could not do much else. Many hand held gaming devices are still special purpose computers.
Ebook readers are another example of special purpose computers. Devices which are made for the sole purpose of reading electronic books such as the Amazon Kindle are special purpose computers.
Automobile onboard computer
Cars manufactured nowadays come with at least one computer. This computer is responsible for, among other things, monitoring engine emissions and adjusting said engine to keep these as low as possible. This computer receives information from a number of sensors and then uses this information to control the operation of the car engine. Most can also detect faults and notify their owners of these through mechanisms such as the “Check engine” light. So automobile onboard computer is an example of special purpose computer.
Many digital cameras are sophisticated, computing devices which give the photographer the ability to delete, move or otherwise manage the captured digital image files. In addition many of these cameras also use digital image processing techniques to enhance, filter or otherwise modify the captured images. Digital cameras are a good example of special purpose computers.
This is a type of transmission that automatically changes a car’s gear ratio as it moves thus doing away with the need for the driver to shift gears manually. In modern cars a computer controls each and every one of these operations.
Automated Teller Machine
ATMs were created to reduce the banking public’s reliance on banking staff and to also improve the convenience of their services by allowing people to access some of these even outside the institutions’ working hours. ATMs allow bank customers to conduct tasks like cash withdrawals and balance enquiries. These devices require computing power in order to facilitate their automatic operation and communication with the bank’s computers. The computers also oversee the authentication of the customer. So an ATM is another example of a special purpose computer.
MRI machine is an example of a special purpose computer. Magnetic resonance imaging is a technique used to capture pictures of the human body together with its physiological processes. MRI scanners use strong magnetic fields together with radio waves to generate images of the internal organs. These machines are wholly controlled by one or more computers. In fact advances in computing technology were crucial to the development of practical MRI which requires a lot of computational power.
A computed tomography (CT) scan is another medical imaging technology which makes heavy use of computing. The desired images are generated by computer-processing a combination of several x-ray measurements which are all taken from different angles. These machines produce cross-sectional images of specific areas of the scanned object without the need for any cutting. This is another example of a special purpose computer in the medical field.
Programmable Logic Controllers (PLCs)
These are industrial digital computers which are specially designed for the control of manufacturing processes and machinery such as assembly lines or robotic devices. PLCs are rugged and are adapted to be highly reliable, fault tolerant and easy to program in industrial environments.
This is a system designed to automatically control the trajectory of an aircraft. It reduces the need for constant manual control of the vehicle by a human operator. Modern autopilot systems use computer software to control the craft. This software reads the aircraft’s current position and then controls the flight control system in order to guide the aircraft. Both the software and the hardware that make up these systems are designed to be highly redundant and reliable.
Hopefully you now understand more about special purpose computers from the above examples.