Classification of the Computer (According to Generation)

According to Generation

Generation & Time Period

First Generation 1946 — 1956

Use of vacuum tubes, large, limited memory, jobs execution coordinated manually, and speed 

up to 10,000

                                  Vacuum tubes

Second Generation 1957— 1963

Use of transistors, more reliable, less heat generation, less power requirement, speed 

200,000 – 300,000

Third Generation 1964 — 1979

• Use of Integrated Circuits (ICS) by printing hundreds and thousands of tiny transistors on to 

small silicon chips

• Speed up to 5 Million Instructions Per Second (MIPS)

• Use of operating systems that automated the running of programs & communications 

between CPU & peripheral devices.

• Availability of hardware independent programming.

Fourth Generation 1980s

Use of LS1 & VLSI circuits, costs fallen to a very low level, large memory & storage, speed up 

to 200 MIPS

Fifth Generation

5 generation computers will be Artificial Intelligence Systems called Al computers, which

simulate the human brain. Expert systems also fall into this category