ICT (Computer)

Types And Components of Computer Systems

1. Hardware : is the parts of computer that you can touch and you can handle.
   Example :  Keyboard, Monitor, Processor, Speaker, Mouse, Hard disks, ROM/RAM, Printer, web cam.
2. Software : is the actual programs consisting of instructions that allow hardware to do a useful job.
   Example : Operating System, Word processing package, Spreadsheet package, Web browser, Database, CAD (Computer - Aided Design), Web design package, Photo editing package.

The main components of a general - purpose computer

• Input devices (Keyboard, Mouse, digital camera, touch screen, microphone, etc)
  Used to get raw data into the computer and ready for processing in the CPU
• Output devices (Speaker, printer, monitor, plotters etc)
  Used to change information given by the computer into sound of image.
• Secondary Storage Devices (Flash disk, DVD R/W drive, portable hard disk drive, etc)
• Processor and internal memory devices.

Central Processing Unit (CPU)

• often called the processor
• it is the brain of computer, it consists of million tiny circuits on a silicon chip
• It controls step-by-step running of the computer system
• it does all the calculation and performs all the logical operations and deals with the data storage and program memory.

Iternal Memory

1. ROM (Read Only Memory) : is a fast permanent memory used for holding instructions needed to start up the computer.
   * It is held on the computer's chip
   * Called non-volatile because file is saved and never lose when the power is off
   * Used to hold instructions to start the computer, which are called the boot programs or BIOS
   *Used to store data that cannot be altered by the user.
2. RAM (Random Access Memory) : Is a fast temporary where programs and data are stored when power is supplied.
   * Held on the computers chip
   * Called volatile memory because contents will disappear when power is off
   * Can be written to and read from
   * Can be altered by the user
   * Holds the software currently used by the user.

Importance of RAM and ROM

 Having more memory means:
* Application runs faster on their own
* More application are able to run at the same time

* Users are able to move quickly between applications

Operating System (OS)

Are the programs to control the hardware directly by giving step-by-step instructions that tells computer what to do.

USES :

• To handle inputs and outputs
• Recognize hardware
• Supervises running of programs
• Handles the storage of data
• Maximizes the use of computer memory
• Handles interrupts and decides what action to take.

Types of Interface used with operating Systems

1. Graphical Users Interface (GUI) : the easy way to use, and have features, such as Windows, Icons, Menus, Pointers, etc.
   Windows   : the screen that is divided into areas
   Icons        : Small pictures to represent commands
   Menus     : Allow users to make selection from list
   Pointers : The little arrow that appears while using windows 
2. Command Line Interface/ Driven Interface : The command must be precisely worded, and this is hard to remember how to do this.

Post-Wimp Interactions

• Pinching : you pinch your fingers together to Zoom in or to spread apart to zoom out.
• Rotating : one finger moves up and the other moves down to rotate the subject as an image.
• Swiping : you swipe your finger over the screen to turn over a page.

Different Types of Computer

1. Mainframe computers :
   * Sophisticated and very strong computer that are used in a very large companies and organizations
   * Used to control huge networks
   * Have parallelprocessors
   
   Advantage of Mainframe computers:
   * Can process huge amount of data
   * Data can be processed very quickly
   * Can run huge networks with hundreds of terminals
   
   Disadvantages of Mainframe Computer
   * it is expensive
   * it must be placed in a special condition, very cold room
   
   Uses :
   * To process huge amount of data
   * To do processing transactions for large companies
   * To process huge volume data needed to produce weather forecast, etc.
2. Personal Computer / Desktop computers:
   Designed to used in one place
   
   Advantage:
   * They have better specification
   * Keyboard is separated from the screen, so both can be adjusted
   * They are cheaper to buy and repair
   * Keyboard and mouse is easier to compare with the keyboard and mouse of laptop
   
   Disadvantage:
   * They are not PORTABLE
   * Lots of wire that should be disconnected when moving the computer
   * We need to spend time copying our files onto removable media.