COMPUTER LECTURES

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COMPUTER HARDWARE

Computer hardware is the physical component of computers and related devices. There are five major types of devices as the followings:-
  1. Input devices
  2. Processing devices
  3. Storage devices
  4. Output devices
  5. Communication devices

  1. Input Devices
    Input devices are pieces of equipment that are used to put the information or instructions into a computer.
    Examples,

    Text input devices
    Keyboard: A device to input text and characters by depressing buttons (referred to as keys)

    Pointing devices
    Mouse: A pointing device that detects two dimensional motion relative to its supporting surface.
    Optical Mouse : Uses light to determine mouse motion.
    Trackball A pointing device consisting of an exposed protruding ball housed in a socket that detects rotation about two axes.
    Touchscreen Senses the user pressing directly on the display

    Gaming devices
    Joystick: A control device that consists of a handheld stick that pivots around one end, to detect angles in two or three dimensions.
    Game pad: A hand held game controller that relies on the digits (especially thumbs) to provide input.
    Game controller: A specific type of controller specialized for certain gaming purposes.

    Image, Video input devices
    Image scanner: A device that provides input by analyzing images, printed text, handwriting, or an object.
    Web cam: A low resolution video camera used to provide visual input that can be easily transferred over the internet.

    Audio input devices
    Microphone : An acoustic sensor that provides input by converting sound into electrical signals.
    Digital camera :

  2. Processing devices
    Processing devices : Act like the brain of a computer, they are housed in the computer system units. The system unit houses the electronic circuitry called the CPU supports processing. The CPU (Central Processing Unit), all instructions the computer will process are processed by the CPU. Random Access Memory (RAM) is a memory that the microprocessor uses to store data during processing
  3. Storage Devices
    Storage devices include a variety of devices used to store data. Storage devices are used to store or save data, programs or output for future use.
    Examples of storage devices
    Hard disk : Used for medium term storage of data.

    CD types
    CD (compact disc) : The most common type of removable media, suitable for music and data.
    CD-ROM Drive : A device used for reading data from a CD.
    CD Writer : A device used for both reading and writing data to and from a CD.

    DVD types
    DVD (digital versatile disc)
    DVD-ROM Drive : a device used for reading data from a DVD.
    DVD Writer : a device used for both reading and writing data to and from a DVD.
    DVD-RAM Drive : a device used for rapid writing and reading of data from a special type of DVD.
    Blu-ray Disc : a high-density optical disc format for data and high-definition video. Can store 70 times as much information as a CD.
    BD-ROM Drive : a device used for reading data from a Blu-ray disc.
    BD Writer : a device used for both reading and writing data to and from a Blu-ray disc.

    Floppy disk : an outdated storage device consisting of a thin disk of a flexible magnetic storage medium. Used today mainly for loading RAID drivers.

    Iomega Zip drive : an outdated medium-capacity removable disk storage system, first introduced by Iomega in 1994. USB flash drive - a flash memory data storage device integrated with a USB interface, Tape drive - a device that reads and writes data on a magnetic tape, used for long term storage and backups.

  4. Output Devices
    Output devices present the results of processing to the user.
    Examples
    Printer : A device that produces a permanent human-readable text of graphic document.
    Speakers : Typically a pair of devices which convert electrical signals into audio.
    Monitor : An electronic visual display with textual and graphical information from the computer.
    CRT : (Cathode Ray Tube) display
    LCD : (Liquid Crystal Display) as of 2010, it is the primary visual display for personal computers.
    Plotter : A plotter is an output device similar to a printer, but normally allows you to print larger images
    Speech synthesiser. Gives you the ability to not only to display text on a monitor but also to read the text to you Data projectors
  5. Communication Devices
    They help computers to communicate with others and access remote information via the internet.

    Examples Modem, NIC etc.
    Modem : This device is used for dial-up connections. It modulates analog carrier signals to encode digital information and demodulates it to decode the information transmitted.
    Network Card : It is one of the most important pieces of hardware as it allows a computer to communicate with other computers over a network. It serves as a networking medium and provides the computers with a MAC address system. A network card is also known as a network adapter

Parts of computer hardware

  1. Mother board : Provides the computer system with all the electrical connections, the basic circuitry and components required for its functioning.
  2. Power supply : This component is responsible for supplying power to the computer.
  3. Computer fan: It is attached to the CPU and is used to lower the temperature of a computer.
  4. Sound Card : Sound cards provide multimedia applications with the audio components.
  5. Video Card : Video card that is also known as the graphics card is a hardware component, which generates and outputs the images to a display.
  6. Random Access Memory (RAM): The main 'working' memory used by the computer, when the operating system loads from disk when you first switch on the computer, it is copied into RAM.
    Data and programs stored in RAM are volatile (i.e. the information is lost when you switch off the computer).
  7. Read Only Memory (ROM): as the name suggests is a special type of memory chip that holds data that can be read but not written to. A good example is the ROM-BIOS chip, which contains read-only software. Often network cards and video cards also contain ROM chips.
  8. Monitor :The television-like screen that displays the visual representation of the computer's contents
  9. Floppy Disk :Storage device used for storing small programs or data. Most diskettes are 3.5 in size and canstore1.4 Megabytes (MB) of information.
  10. Hard Disk :Storage device found in the computer which is used for storing instructions and data. Hard disks are capable of storing gigabytes(GB) of data (thousands of Megabytes).
  11. CD-ROM :Compact Disk Read Only Memory storage media. CD-ROMs have a similar appearance to audio CDs. Computer programs are often stored on these discs because of their large storage capacity.
  12. CD-R/RW :A compact disk, similar to a CD- ROM, except Some types are capable of being recorded multiple times.
  13. Mice :A hand held device which controls cursor movements on the screen. A button on the mice can be used to select programs/files by clicking once on the program/file icon. It can also be used to launch programs/files by rapidly clicking twice on the icons (double clicking).

Types Of Computer Memory

  1. Random Access Memory (RAM)
  2. Read Only Memory (ROM)

Random Access Memory (RAM) is where the operating system is loaded and also where your applications are copied to when you load an application, such as a word processor or database program.

Read Only Memory (ROM) is a special chip held on a motherboard of a computer's system. It contains software that is required to make a computer work with an operating system

How Computer Memory Is Measured
A character is made of bits.

Bit:
All computers work on a binary numbering system, i.e. they process data in one's or zero's. This 1 or 0 level of storage is called a bit.

Byte:
A byte consists of eight bits.

Kilobyte:
A kilobyte (KB) consists of 1024 bytes.

Megabyte:
A megabyte (MB) consists of 1024 kilobytes.

Gigabyte:
A gigabyte (GB) consists of 1024 megabytes