Significant Developments which led to Modern Electronic Computer


  1. 1845 Boolean Algebra was developed by George Boole.
  2. 1890 Herman Hollerith used Punched Cards for storing data.
  3. 1900 Valdemar Poulson developed recording devices like tapes and drums coated with thin films of magnetic oxide.
  4. 1906 Lee do Forest invented Thermionic valve. Values were the first devices to be used in the modern digital computers.
  5. 1937 Alan Turing, A British Mathematician, showed how a problem can be solved with logical steps. These logical steps could be broken into a set of small and simple instructions.
  6. 1938 Claude Shannon, an electrical engineer established the fact that electronic switching circuits can be employed to perform logic and arithmetic operations.
  7. 1944 Professor Howard Aiken developed a fully automatic electrically driven machine. This was called Automatic Sequence Controlled Calculator (ASCC) or Harvard Mark I. During the Second World War electronic valve based calculating machines were used in 1941. These were called Z3 and Z4. These machines were produced in Germany by Konrad Zuse. Later on they were destroyed by Allied Bombing. In 1943, another valve based machine called COLOSSUS was used at the British Intelligence Establishment at Bletchley Park.
  8. In 1946, J. Presper Eckert and John Mauchly at Pennsylvania University completed a machine called Electronic Numerical Integrator and Calculator (ENIAC). This machine could perform 5000 additions per second.
  9. In 1946 itself, John Von Neumann set out a summary of the design requirements for the modern electronic computer.

The main points were:

  • Binary codes should be used for representation of data.
  • Computer should be capable of processing both data and instructions.

This includes modification of programs.

Computer Generations

The development of computers has passed through various stages. This development is divided into five categories:

  • First Generation (1942 to 1960)
  • Second Generation (1960 to 1965)
  • Third Generation (1965 to 1975)
  • Fourth Generation (1975 to date)
  • Fifth Generation (Coming Generation of Computers)

First Generation(1942-1960)


The computer of this generation was developed in 1946 by Sir J.P. Eckert and J.W.Mauchly. This computer was named as Electronic Numerical Integrator and Calculator (ENIAC). It was completed in a time period of 4 years. This machine contained 18000 vacuum tubes and 70,000 resistors and there were 60,000 button and switches in this calculator. The weight of this machine was 28 tones and the consumption of electricity was 150 KW. After use it got heated and had to be cooled by water. It took only 200 millisecond to perform one addition. This calculator became very famous due to its speed.

Other computers of first generation are:
UNIVAC-1, IBM-701 and IBM-650, Data matrix-1000, EDSAC, MARK II, MARK III.

Limitations of First Generation Computers

  • These computers contained vacuum tubes and were costly.
  • The consumption of electricity was much more and heating effect was more. Cooling was necessary during and after use.
  • The speed of these computers was very slow.
  • They were very large in size.
  • The life span of these computers was short and were not very reliable.
  • The level of accuracy was low.
  • Fault-detection was very difficult.

Second Generation (1960-1965)

The computers of second generation are based on the invention of transistor (1948). Transistors were very small components as compared to vacuum tubes and the consumption of electricity was negligible as compared to first generation computers. The heating effect was low and size was comparatively small.

Computers of Second Generation:
CDC-3600, IB-700, IBM-1401, ICL-1901, UNIVAC-1108, IBM-7094, RCA-501, CDC-1604

Third Generation (1965-1975)

The computers of this generation could be developed after the development of Integrated Circuit. Integrated circuits were made of silicon. A single 1C could hold a number of transistors and resistors. This was also called Chip. The computers of this generation were 1000 times fast as compared to first generation computers and their cost was comparatively low. The memory of these computers was much more and data processing became very easy.

Computers of Third Generation:
CDC-1700, ICL-2903, PDP-11/45

Fourth Generation (1975 – To date)

The further development of 1C opened the doors for development of this generation. 1C could hold thousands of transistors on a single component. This technique is known as Large Scale Integrated Circuits. The computers using these circuits are called micro computers. These computers were manufactured by an American Company-Micro Instrumentation and Telemetry Co. In 1981 IBM manufactured a Personal Computer and after that computers were installed almost at all commercial organizations, schools, colleges, factories and offices.

Computers of Fourth Generation:
Intel-4004, Apples I & II, DCM-Spectrum

Features of computers of Fourth Generation

  • Size is very small and speed is very high.
  • Perform job for a very long duration.
  • Cheap as compared to previous generations.
  • Memory and data processing capacity is very large.
  • Minimum energy (electricity) consumption.
  • Heating effect very low.

Fifth Generation

The computers of this generation are still to come. The scientists are making their full efforts to develop such computers which are capable of taking decisions itself. In this way computers will supersede human in terms of calculations, thinking and decision making. The Japanese have thought to name this generation as Knowledge Information Processing System (KIPS). They are inventing such languages which could fulfill their dream.

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