Third Generation(1965-1971):

• ​The development of the integrated circuit was the hallmark of the third generation of computers.
• Transistors were miniaturized and placed on Silicon chips called semiconductors.
• Instead of punched cards and printouts, users interacted with third-generation computers through keyboards and monitors and interfaced with an operating system.
•  It allowed the device to run many different applications at one time.

First Generation(1942-1955): 

• The first-generation computers used vacuum tubes for circuitry and magnetic drums for memory.
• They were often enormous and taking up the entire room.
•  First-generation computers relied on machine language.
• They were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctions.
•  The UNIVAC and ENIAC computers are examples of first-generation computing devices.

Second Generation(1955-1964):

• The computer made in the second generation was completely based upon transistors.
• Transistors replaced vacuum tubes in computers.
• It was invented at Bell Labs by Walter H. Brattain (1902-1987), John Bardeen (1908-1991), and William B. Shockley (1910-1989) in 1947.
• In the computers of the second generation, punched cards and printouts were used for inputs and outputs.
• The TX-0 was the first computer that used transistors, It was released in 1956.
• These second-generation machines were used for a wide variety of business and scientific jobs and used high-level programming and assembly languages such as FORTRAN (Formula Translator) and COBOL (Common Business Oriented Language).
• The second-generation computers had several features:
  • ​Computers made in the second generation used transistors that made them more reliable, smaller in size, faster in speed, more energy-efficient, and cheaper compared to the first generation of computers.
  • They contain magnetic storage disks and magnetic core memory.
  • They used high-level languages such as FORTRAN and COBOL and allowed communication with the help of a telephone line.
  • As compared to the first generation of computers, the data processing time reduced from milliseconds to microseconds.

Fourth Generation(1971- up to till now):

• The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip.
• The Intel 4004 chip, developed in 1971, located all the components of the computer.
• From the central processing unit and memory to input/output controls on a single chip.
• Fourth-generation computers also saw the development of GUIs, the mouse, and handheld devices.