Generation of computers

A computer system is combination of hardware and software so the generation covers both hardware and software. The development of computer took place in five district phases known as Generation. These generations are categorized by their technology as follows:

First Generation Computers

The first generation computers used vacuum tubes. They were very large in size and programming on them was very difficult. Some of the computers of this generation are as follows:-

·               MARK – I :

  This was the first electronic computer developed by Howard Aiken. It was about 15metres long and the wires connecting the various parts of the machine were about 800 Km long. The main advantage of this computer was that it was fully automatic and much more reliable than other electronic computers.

·               ENIAC :

            This was the first fully electronic digital computer developed by J.Presper Eckert and John Mauchly. The full form of ENIAC is Electronic Numerical Integrator And Computer. It contained approximately 17,500 vacuum tubes, occupied 680sq.ft area and weighted more than 27000Kg. Since ENIAC was initially not a stored program machine, it had to be programmed by manual rewiring for each task.

·               EDVAC :

            EDVAC was also developed by the makers of ENIAC. It was a stored program machine unlike its predecessor. The full form of EDVAC is Electronic Discrete Variable Automatic Computer.

·               UNIVAC I :

            UNIVAC I was the first commercially available electronic computer developed by J.Presper Eckert and John Mauchly. It was also the first computer to handle both numeric and text data. The full form of UNIVAC I is Universal Automatic Computer I

Limitations of first-generation computers

·                     The major limitations of first generation computers were :

·                     The operating speed was very low.

·                     Power consumption was very high.

·                     They required large space for installation.

·                     The Programming capability was quite low.

·                     Quit larger, they generate lot of heat require special housing.

·                     The Medium internal store.

Second-Generation Computers

The second generation of computer marked by either magnetic drum or magnetic core storage and later use of transistor in place of vacuum tubes second generation lasted until the first half 1960’s. These generations are categorized by their technology as follows:

             ICT(ICL) 1300, IBM 1401

Limitations of second-generation computers were :

• They used transistors as their main component.
• They were smaller, faster and more efficient than first-generation computers.
• They also contained all the components we associate with modern-day computers like printer, memory, disk storage, operating system.
• They are cheaper than the first generation computers.
• Maintenance requirement is still high.
• Very costly.

Third-Generation Computers

The third generations of computer replaced transistors with Integrated Circuits (ICs).This ICs are very small in size, also known as silicon chip. A single chip contained thousand of transistors. These generations are categorized by their technology as follows:

            IBM-360 series, ICL – 1900, ICL – 2903, PDP – 11/45

Limitations of third-generation computers were :

·         They used Integrated Circuits, popularly known as chips.

·         These computers were smaller than the second-generation computers.

·         Capacities of main memory were greatly enlarged.

·         They used an operating system that allowed machines to run many different programs simultaneously.

·         Power requirement became less.

·         Maintenance of IC required sophisticated technology.

Fourth-Generation Computers

The fourth generation of computer replaced LSI chip with Integrated Circuits (ICs). A single chip contained thousand of transistors. Semiconductor memories replaced magnetic core memories.

Limitations of fourth-generation computers were :

·         They used Large –scale Integrated Circuits and Very Large –scale Integrated Circuits (VLSIC).

·         They have very high computing power and extremely large memories than earlier computers.

·         Storage devices have greatly improved and cost is less.

·         Computers can be linked together to share memory space, software, information and communicate with each other.

·         Manufacture of LSI chips required sophisticated technology.

Fifth-Generation Computers

Till the fourth-generation of computers, the major stress was on improving the hardware. This resulted in smaller size and fast speed of computers. The only drawback was the lack of thinking power. This gap was filled up by the fifth-generation computers and are being referred to as Super Computers. They have a very high storage capacity, high speed, ability to do highly sophisticated operations and the capability to make decisions of the right kind. These computers are based on Artificial Intelligence.