Classification of Computers

According to the generation

• First generation computers - Vacuum tubes were used to design computers of this generation.
• Second generation computers - Transistors were used to design computers of this generation.
• Third generation computers - Integrated Circuits (IC) were used to design computers of this generation.
• Fourth generation computers - Microchips or Microprocessors were used to design computers of this generation.
• Fifth generation computers - Computers that are supposed to have the thinking ability are called fifth generation computers. Scientists are trying hard to develop the fifth generation computers using 'Artificial Intelligence'.

According to the size

• Super computers - Computers which are designed for a specific purpose with very high performance and capabilities are called as such. 
• Mainframe computers - These are the large scale computers. 
• Mini computers - Medium size computers can be called mini computers. 
• Micro computers - Extremely small computers that can be called micro computers.

According to the technological development

• Personal computers (PCs) - Computers designed for individual's use are called personal computers and this type of computers has been widely developed now. Personal computers are also known as ' Desktop Computers'.
• Laptop computers - These are portable computers designed to be carried about. These are known as the 'Note book computers' or 'Portable computers'.
• Palmtop computers - These are the computers that can be held on palm. Palmtops are also called 'Personal Digital Assistants' (PDAs).
• Work station computers - The name 'Workstation computers' is used for desktop computers made with high capacities. These are widely used to design more complex graphic designing and 3D animations and also serve as server computers.

According to the purpose

• Computers designed for usual and day - to - day activities are called General Purpose Computers.
• Computers designed for special purposes such as scientific experiments, battle operations, discovery of oil rigs etc.. are called Special Purpose Computers.

According to the design technology

• Digital computers - Computers designed by using the binary digital number system are called digital computers.
• Analog computers - Computers which are designed considering the physical data such as temperature, thrust, and pressure are called analog computers.
• Hybrid computers - A combination of the above two types of computers can be called hybrid computers.