INPUT OUTPUT MEMORY DEVICES

• The device used to accept the data and instructions from the user is called input device. \
• Input devices are capable of converting data into a form which can be recognized by computer
• Most common input device is keyboard
• Standard keyboard-105/108: QWERTY keyboards are the most common
• Ergonomic keyboard- A keyboard that is designed to reduce the risk of musculoskeletal disorders
• Wireless keyboard- A wireless keyboard that connects to a computer via a wireless network.
• Virtual keyboard- A keyboard that is displayed on the screen instead of being physically attached to the computer.
• Compact keyboard- These keyboards usually don't have numerical keypad that is present on the right side used mainly in laptops.
• MOUSE- Mechanically Operated User Serial Engine
• Mechanical mouse- A mouse that uses a ball to move the pointer on the screen.
• Optical mouse- Uses a laser beam to detect movement of the mouse.
• Joystick- A device that allows a player to control the movement of a virtual or real object.
• Scanner- A device that reads and converts printed text into electronic form.
• Optical mark reader- Reads pencil marks on paper or plastic cards.and converts them into binary code.
• Optical character recognization- the process of converting printed text into a machine-readable format
• Magnetic ink character recognition- MICR is a technology that uses magnetic ink to encode information on paper.
• Output device- A device that displays the results of the computer's processing.
• Monitor- Oputput device most commonly used mostly called display screen or VDU
• Different types of monitors are:

  CRT(cathode ray tube)

  LCD(Liquid crystal display)

  TFT(Thin film transistors)

  LED(Light emitting diode)
• Printer- A device that converts the information in a computer file into a form that can be printed.
• Impact printers-create characters and images by physically striking an inked ribbon against the printing surface.
• Line printer- high-speed impact printer that prints one line of text at a time.
• Dot matrix printer- uses a dot matrix to print the image on paper.
• Non- impact printer- A printer that does not require a computer to operate.
• Thermal printer- A printer that uses heat to transfer ink onto paper.
• Laser printer- A printer that uses a laser to transfer an image from a computer to paper.
• Inkjet printer- A printer that sprays tiny droplets of ink onto paper to create an image.
• Plotter-Used to draw shapes on paper based on commands from the computer.
• Speakers-Signals from analog/ digital are converted into audiable frequency in the speakers and produse voice output
• Projectors- A device that projects images or text onto a screen or wall.
• Computer memory- Stores data and instructions that are currently being used by the computer.
• Primary memory- Stores data and instructions that are currently being used by the processor.
• Random access memory- RAM is a type of computer memory that can be accessed randomly, meaning that the computer's processor can access memory locations without knowing in advance where data is stored.
• 1 byte=8bits
• 1 nibble=4 bits
• Static RAM-Cache memory due to high speed. stores info as lpng as power supply is on
• Dynamic RAM-Uses transistors and capacitors and consumes less power
• Synchronous dynamic RAM- A type of RAM that is designed to be read and written simultaneously.
• Double data rate RAM- DRAM is a type of random access memory that uses two data lines to store data.
• Read only memory- A type of memory that can only be read from but not written to.