Hardware mindmap

Hardware mindmap

1. Hardware

   • Input Devices
     • Keyboard
       • The most common input device to enter text, numbers and instructions into computers
       • Disadvantages
         • Users with limited arm/wrist use find keyboards difficult to use.
         • slow when compared to direct data entry (e.g. optical mark recognition)
         • takes up physical space
       • braille keyboard
         • The braille keyboard has raised dots to identify the keys. This will help the blind people input data into the computer.
       • concept keyboard
         • The concept keyboard uses icons or phrases instead of standard letters. They are often used in fast food restaurants, supermarkets, shops where a single key represents an item.
     • Mouse
       • Uses
         • used for opening, closing and minimising software
         • used for grouping, moving and deleting files
         • very useful when editing images, for example controlling the size and position of a drawing
         • to select icons
       • Advantages
         • enables rapid navigation through applications and the Internet
         • are small and so takes up little physical space
       • Disadvantages
         • people with restricted hand/wrist movement can have difficulty
         • difficult to use if there is no flat surface
     • Touchpads
       • Touchpads are used in laptop computers as a pointing device.
       • Advantages
         • enables rapid navigation through applications and the Internet
         • integrated into the laptop, aids portability
         • can be used when when there are no flat surfaces
         • faster to select an option compared to using a keyboard
       • Disadvantages
         • people with restricted hand/wrist movement can have difficulty
         •  more difficult to use when compared with a mouse
         •  can be more difficult to use when doing certain operations such as “drag and drop”
     • Trackerballs
       • Uses
         • has the same pointing/cursor control capability as a mouse
         • used in control room environment where it is faster and more robust than a mouse
       • Advantages
         • easier for peope with limited hand/wrist movement
         • since it is stationary, it takes up less desk space
       • Disadvantages
         • more expensive since they are not a standard equipment
     • Remote Control
       • Uses
         • commonly found in home entertaiment devices
         • used in industrial applications to remotely control processes, stop and start machinery, etc
       • Advantages
         • can be operated from a distance
         • some chemical processes are hazardous, so it is safer to operate equipment from a distance
       • Disadvantages
         • people with restricted hand/wrist movement can have difficulty
         • signal between the control and device can be easily blocked
     • Joysticks
       • most popular input device for computer games ,used in simulators (e.g. flight simulators) to mimic actual controls
       • Advantages
         • easier to control game actions
         • can control game actions by varying the pressure, speed and direction of the joystick
     • Touch Screens
       • User chooses an option by touching the button/icon on the screen, without the need for any pointing device.
       • Advantages
         • faster data entry of options
         • easier to choose options
         • a user-friendly method for keying in data
         • prevents people from keying in information which could potentially corrupt the computer system
       • Disadvantages
         • limited number of options available
         • screen can get very dirty with constant touching
       • Uses
         • used where selections are made on screen used in PDAs mobile phones and satellite navigation systems
     • Magnetic stripe readers
       • The magnetic stripe found, for example, on the back of a credit card, debit card, ATM card contains useful information such as the account number, expiry date and start date.
       • Advantages
         • faster data entry
         • error free since no typing is involved
       • Disadvantages
         • if the magnetic stripe gets damaged, the data is lost
         • since the information is not human readable, this can be a disadvantage in some situations
     • Barcode readers
       • Uses
         • used in supermarkets and other shops where the goods are marked with a barcode; libraries to scan library cards and books
       • Advantages
         • faster data entry and fewer mistakes
         • enables automatic stock control
         • when an item price is changed, only the central database needs to be updated. There is no need to change the prices individually on each item
       • Disadvantages
         • can be relatively expensive to administer
     • Optical Mark Recognition (OMR)
       • Uses
         • used to read questionnaires, multiple-choice questions, etc where responses are in the form of shaded areas
       • Disadvantages
         • there can be problems if the forms are not filled in correctly
       • Advantages
         • a very fast way of inputting the results of a test, survey, etc
         • more accurate than keying in the data since there is no typing
     • Optical Character Recognition (OcR)
       • Software that takes scanned text and converts it into a computer readable form.
       • Disadvantages
         • may not be accurate as system still has difficulty reading handwriting
       • Advantages
         • faster data entry
         • depending on the source, number of errors is reduced since there is no manual data entry
     • MAGNETIC Ink Character Recognition (MICR)
       • Disadvantages
         • only certain characters can be read
       • Advantages
         • no manual input, thus errors are reduced
       • Read characters printed in a special ink. For example, the characters at the bottom of a bank cheque.
     • Digital Cameras
       • Advantages
         • easier to produce better quality photographs than with a traditional camer
         • memory card can store several hundred photographs
         • easier and faster to upload photographs to a computer
         • no need to develop film and print out photographs
         • easy to delete an image from memory
       • Disadvantages
         • some artistry lost since software now corrects errors in the photographs (e.g. incorrect exposure, removal of red eye, etc)
     • Webcams
       • Disadvantages
         • limited features and picture is often of poor quality
         • needs to be connected to the computer (not so with laptops, though)
       • Advantages
         • allows people too keep in contact with each other without travelling
       • Connected directly to the computer through a USB port and they do not have a memory. Used to enable video conferencing.
     • Microphones
       • Uses
         • used to input speech/sounds to be used in various applications (e.g. presentation, special effects)
         • used in voice recognition software (e.g. convert speech into text). This is useful for people with limited hand/wrist movement.
       • Advantages
         • faster to read in text than to type it in using a keyboard
       • Disadvantages
         • sound files can use up a lot of computer memory
         • voice recognition software is not as accurate as typing in manually (e.g. cannot distinguish between words that sound alike)
     • Sensors
       • A device which measures some physical quantity which is continuously changing (e.g. temperate, light, etc) and inputs it to a computer. Sensors are usually used in monitoring and control applications.
       • Disadvantages
         • faulty sensors can give false results
       • Advantages
         • readings ar continuous, so there is no break in the monitoring
         • readings are generally more accurate than readings taken by human operators
     • Graphics Tablets
       • Used with a stylus to produce freehand drawings. The images produced can then be stored in a file on a computer.
       • Advantages
         • an accurate method of drawing compard with using a mouse or a trackerball
       • Disadvantages
         • more expensive than other pointing devices, such as a mouse
     • Light Pens
       • Light-sensitive pen-like device that contain sensors that send signals to a computer whenever light changes are detected. It is placed against monitor when used and used commonly to edit digital images.
       • Advantages
         • easy to use
       • Disadvantages
         • problems with lag when drawing on screen
         • only work with CRT (cathode ray tube) monitors at the moment
   • Output devices
     • Monitor
     • Printers
       • Laser printers
         • best for fast high quality high volumne printing
       • Plotters
         • can produce highly accurate, very large drawings (blueprints of buildings) and posters
       • Inkjet printers
         • printing may “smudge”
       • Dot matrix printers
         • an impact printer, alow, noisy and output is not good quality
         • can produce carbon-copies
       • Braille printer
         • produce raised dots printouts to help blind people read output from computer
     • Speakers
       • can help blind/partially sighted people through audio output of text
       • used to output sound from multimedia presentations