1. Digital Computer High speed programmable ,electronic device
Recognize data by counting discrete signals representing either high(1) or low(0) voltage state of electricity.
Accurate
Output is continuous but obtain when computation is completed.
Real time example: Digital watch

2. Micro Computer(Personal Computer)
Consists of microprocessors, microchips and storage devices.
Suitable for personal usage.
Common PC suppliers are HP, DELL, HCL,
Compaq etc.

3. Mini Computer Small general purpose computer
More memory and processing capabilities than micro computers.
Used as servers in the network environment
Common mini computers are PDP-II, PDP-45.
Mini Computer System

4. Mainframe Computer
Several computer terminals (keyboard, monitor etc.) are plugged into a single mainframe.
Fast processing
Large storage
Occupy lot of space and require air conditioning
Non portable computer
Skilled staff is required to operate.
Common mainframe series are Superry, DEC, ICL, PDP 370 etc.

5. Mainframe Computer

6. Super Computer Most powerful and most expensive.
Fast. Can perform millions of processes in a second.
Ideal for handling large and highly complex problems that require large processing such as weather forecasting, remote sensing, image processing etc.
Large memory.
PARAM is India's first super computer.

7. Super Computer

8. Laptop and Hand Held Computer
Very small in size and light in weight.
Portable

9. Some other digital computers
Tablet PC
Smart Phone