5.1.1 - Computer Systems: Types of System

Types of Computer Systems:

1. Non-portable:
   1. Desktop computers - these systems are mains powered and are typically used by home, office and school users. They would typically consist of the computer itself (complete with hard disk drive and floppy disk drive) and peripherals such as a screen, a mouse, a keyboard and a CD or DVD drive.
      • Advantages: Relatively cheap and easy to add expansion cards, hard drives, memory etc.
      • Disadvantages: Can take up a lot of space and are not easily moved.
2. Portable:
   1. Notebooks (laptops) - these are small (typically 30cm x 20cm), light and easy to carry. The screen is on the inside top flap which hinges open to show the keyboard and mouse controls. They are designed to run on rechargeable batteries or the mains and can contain many of the features available on a desktop computer. Touch pads or a button are usually used to control the screen pointer.
   • Advantages: Portable due to their size and ability to run on batteries.
   • Disadvantages: Expensive for their processing power compared to desktop computers. You cannot use standard expansion cards. Keyboards and screens not as good for extended usage.

   2. Palm-tops & PDAs (personal digital assistants) - These are small hand-held computers. They are usually supplied with software such as a diary, a contacts database, and some form of word processor. Many now have email facilities and even spreadsheets and databases. They either use a small keyboard or a touch-sensitive screen and handwriting recognition software. They can be linked to larger computers directly by cable or through a docking station or using an infra-red link.

   • Advantages: Very portable due to their size and ability to run on batteries.

   • Disadvantages: Relatively expensive, limited expansion, non-keyboard versions can be slow to input data.