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Output devices

An output device is any peripheral that receives data from a computer, usually for display, projection, or physical reproduction. For example, the image shows an inkjet printer, an output device that can make a hard copy of any information shown on your monitor, which is another example of an output device. Monitors and printers are two of the most common output devices used with a computer.

Types of output devices

  1. 3D Printer
  2. Braille embosser
  3. Braille reader
  4. Flat panel
  5. GPS
  6. Headphones
  7. Computer Output Microfilm (COM)
  8. Monitor
  9. Plotter
  10. Printer (Dot matrix printer, Inkjet printer, and Laser printer)
  11. Projector
  12. Sound card
  13. Speakers
  14. Speech-generating device (SGD)
  15. TV
  16. Video card

A computer can still work without an output device. However, without an output device, a user have no way of determining what the computer is doing, if there are errors, or if it needs additional input. For example, a user can disconnect your monitor from your computer, and it will still function, but it’s not going to be very useful.

Laser Printer

A laser printer is a popular type of personal computer printer that uses a non-impact (keys don’t strike the paper), photocopier technology. When a document is sent to the printer, a laser beam “draws” the document on a selenium-coated drum using electrical charges. After the drum is charged, it is rolled in toner, a dry powder type of ink. The toner adheres to the charged image on the drum.

The toner is transferred onto a piece of paper and fused to the paper with heat and pressure. After the document is printed, the electrical charge is removed from the drum and the excess toner is collected. Most laser printers print only in monochrome. A color laser printer is up to 10 times more expensive than a monochrome laser printer.

IBM introduced the first laser printer in 1975 for use with its mainframe computers. In 1984, Hewlett-Packard revolutionized laser-printing technology with its first LaserJet, a compact, fast, and reliable printer that personal computer users could afford. Since then, laser printers have decreased further in price and increased in quality. Hewlett Packard continues to be the leading manufacturer with competitors including Lexmark, Okidata, and Xerox.

The laser printer is different from an inkjet printer in a number of ways. The toner or ink in a laser printer is dry. In an inkjet, it is wet. Over time, an inkjet printer is about ten times more expensive to operate than a laser printer because ink needs replenishing more frequently. The printed paper from an inkjet printer will smear if wet, but a laser-printed document will not. Both types of printer operate quietly and allow fonts to be added by using font cartridges or installing soft fonts. If your printing needs are minimal, an inkjet printer is sufficient. But if your printing volume is high, consider buying a laser printer.

Inkjet printer

An inkjet printer is a computer peripheral that produces hard copy by spraying ink onto paper. A typical inkjet printer can produce copy with a resolution of at least 300 dots per inch ( dpi ). Some inkjet printers can make full color hard copies at 600 dpi or more. Many models include other devices such as a scanner, photocopier, and dedicated faxmachine along with the printer in a single box.

In the inkjet printing mechanism, the print head has several tiny nozzles, also called jets. As the paper moves past the print head, the nozzles spray ink onto it, forming the characters and images. An inkjet printer can produce from 100 to several hundred pages, depending on the nature of the hard copy, before the ink cartridges must be replaced. There is usually one black ink cartridge and one so-called color cartridge containing ink in primary pigments (cyan, magenta, and yellow). Some inkjet printers use a single cartridge with cyan, magenta, yellow, and black ink. A few models require separate cartridges for each primary pigment, along with a black ink cartridge.

The principal advantage of inkjet printers is the fact that most of them are inexpensive. Inkjet printers are often given away at computer superstores along with the purchase of a personal computer or substantial peripheral. Even the cheapest inkjet printers are satisfactory for most of the needs of personal computer users. High-end inkjet printers can render digital images on special paper, with quality rivaling that of professionally produced glossy or matte photographs. Another advantage of inkjet printers is their light weight and modest desktop footprint. Many models are easy to transport, and are preferred by traveling salespeople for this reason alone.

Dot matrix printer

A type of printer that produces characters and illustrations by striking pins against an ink ribbon to print closely spaced dots in the appropriate shape.

Dedicated and Embedded Systems

Embedded system is asingle dedicated purpose, within a larger system, usually limited on resources. (e.g. power-train control module of a vehicle). Dedicated system is obviously dedicated purpose too, but mostly stand-alone and high performance. (e.g. database/printing sever)

One characteristic that easily puts a system into the “embedded systems” category is a very limited or non-existent user interface. That won’t be true of all embedded systems; some embedded systems will have a complex user interface that is dedicated to the system’s purpose.

For example, many would consider a wireless router to be an embedded system. The main user interface will be some LEDs and maybe a button or two. There is also often an HTTP-based user interface. But many embedded systems may have no user interface. It only ever communicates with other systems, never directly to a user.

Embedded systems are designed to do some specific dedicated task within larger system, so their hardware and software are tightly coupled and by design they have no features to expand (modify) it’s hardware or re-program its software for different task . The software component (firmware) usually can be provided only by manufacturer, in a form of compiled binary image. So embedded systems are essentially black boxes, there is no reason to create standards for interchangeability on what is inside that box. Example: printer, network router.

Pervasive Computing

Pervasive computing, also called ubiquitous computing, is the growing trend of embedding computational capability (generally in the form of microprocessors) into everyday objects to make them effectively communicate and perform useful tasks in a way that minimizes the end user’s need to interact with computers as computers. Pervasive computing devices are network-connected and constantly available.

Unlike desktop computing, pervasive computing can occur with any device, at any time, in any place and in any data format across any network, and can hand tasks from one computer to another as, for example, a user moves from his car to his office. Thus, pervasive computing devices have evolved to include not only laptops, notebooks and smartphones, but also tablets, wearable devices, fleet management and pipeline components, lighting systems, appliances and sensors, and so on.

The goal of pervasive computing is to make devices “smart,” thus creating a sensor network capable of collecting, processing and sending data, and, ultimately, communicating as a means to adapt to the data’s context and activity; in essence, a network that can understand its surroundings and improve the human experience and quality of life.

Often considered the successor to mobile computing, ubiquitous computing and, subsequently, pervasive computing, generally involve wireless communication and networking technologies, mobile devices, embedded systems, wearable computers, RFID tags, middleware and software agents. Internet capabilities, voice recognition and artificial intelligence are often also included. Pervasive computing applications can cover energy, military, safety, consumer, healthcare, production and logistics.

The term pervasive computing followed in the late 1990s, largely popularized by the creation of IBM’s pervasive computing division.

The vision of pervasive computing is computing power widely dispersed throughout daily life in everyday objects. The internet of things is on its way to providing this vision and turning common objects into connected devices, yet, as of now, requires a great deal of configuration and human interaction.


Deploying Pervasive Technologies in a Hospital

  1. Coordination of operations in large hospital intense
  2. iHospital system: – Large wall displays, PCs, mobile phones
  3. Maintain shared view of available resources
  4. Scheduling new surgeries
  5. Tracking doctors/nurses and required resources
  6. Coordination of resources
  7. Monitoring procedures, doctors and resources – Uses location tracking and video streaming


As a cross-application, the communications area affects all forms of exchange and transmission of data, information, and knowledge. Communications thus represents a precondition for all information technology domains.


Tracking logistical goods along the entire transport chain of raw materials, semi-finished articles, and finished products (includingtheir eventual disposal) closes the gap in IT control systems between the physical flow and the information flow. This offers opportunities for optimizing and automating logistics that are already apparent today.

Motor traffic:

Automobiles already contain several assistance systems that support the driver invisibly. Networking vehicles with each other and with surrounding telematics systems is anticipated for the future.


The military sector requires the provision of information on averting and fighting external threats that is as close-meshed, multi-dimensional, and interrelated as possible. This comprises the collectionand processing of information. It also includes the development of new weapons systems.


In the smart factory, the flow and processing of components within manufacturing are controlled by the components and by the processing and transport stations themselves. Ubiquitous computingwill facilitate a decentralized production system that will independently configure, control and monitor itself.


The smart objects of ubiquitous computing allow for ew business models with a variety of digital services to be implemented. These include location-based services, a shift from selling products to renting them, and software agents that will instruct components inubiquitous computing to initiate and carry out services and business transactions independently.

Inner security:

Identification systems, such as electronic passport and the already abundant smart cards, are applications of ubiquitous computing in inner security. In the future, monitoring systems will become increasingly important—for instance, in protecting the environment or surveillance of key infrastructure such as airports and the power grid.

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