Input Devices
Input Devices take data and put it into a form the computer can process.  Examples of input devices are:

• keyboard
• Mouse
• Scanner
• Bar Code Reader
• Video Camera
• Trackball
• Graphics Tablet

The System Unit
The system unit consists of electronic circuitry with two parts:

• Central Processing Unit (CPU) -  controls and manipulates data to produce information.
  
• Memory (primary storage) -  holds data, program instructions, and processed data.  Two types of memory exists:
  • Read Only Memory (ROM)
  • Random Access Memory (RAM)
    
     

Secondary Storage

Secondary storage stores data and programs.  Examples of storage medias are:

• Floppy disks- removable 3½ inch plastic disks
• Hard disks- non-removable; internal disk drive
• Optical disks- removable; CD or DVD disks
• Zip Disks-  High capacity removable disks
  
  

Output Devices

Output devices output processed information from the CPU.  Examples of  output devices are:

• Monitor
• Printer
• Computer Projection Panel
• Plotter
• Sound Card
  
  

Communication Devices

These send and receive data and programs from one computer to another.  An important communication device is the modem which allow digital equipments (such as computers) to transmit and receive data on a telephone line.

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