Computers Generations

The history of computer development is often referred to in reference to the different generations of computing devices.Each generation of computer is characterized by a major technological development which in turns changed the way computers operates, resulting in increasingly smaller, cheaper, powerful, faster, efficient and more reliable

First Generation (1940-1956)
The first computers used vacuum tube technology for circuitry and magnetic drums for memory, and were very large in size, taking up entire rooms. 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.

First generation computers relied on machine language to perform operations, and they could only solve one problem at a time. Machine languages are the only languages understood by computers. While easily understood by computers, machine languages are almost impossible for humans to use because they consist entirely of numbers, which means that they can be operable only by the programmers.

The UNIVAC(UNIVersal Automatic Computer) and ENIAC(Electronic Numerical Integrator And Calculator) computers are examples of first-generation computing devices.
The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951. The ENIAC, weighing 30 tons, using 200 kilowatts of electric power and consisting of 18,000 vacuum tubes,1,500 relays, and hundreds of thousands of resistors,capacitors, and inductors, was completed in 1945.

Second Generation (1956-1963)
In the second generation computers Transistors replaced vacuum tubes, but still relied on punched cards for input and printouts for output. Transistor is a device composed of semiconductor material that amplifies a signal or opens or closes a circuit. Invented in 1947 at Bell Labs, transistors have become the key ingredient of all digital circuits, including computers. Today's latest microprocessor contains tens of millions of microscopic transistors.

The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper,more energy-efficient and more reliable than their first-generation predecessors. Though the transistor still generated a great deal of heat that subjected the computer to damage, it was a vast improvement over the vacuum tube.



Second-generation computers moved from cryptic binary machine language to symbolic, or assembly, languages,which allowed programmers to specify instructions in words. High-level programming languages were also being developed at this time, such as early versions of COBOL and FORTRAN. These were also the first computers that stored their instructions in their
memory, which moved from a magnetic drum to magnetic core technology.
Eg : IBM 7094

Third Generation (1964-1971)
Transistors still generated a great deal of heat, which damaged the computer's sensitive internal parts. The development of the IC(Integrated Circuit) in 1958 made a replacement for transistors to produce third generation of computers.

The IC combined three electronic components onto a small silicon disc, which was made from quartz. Scientists later managed to fit even more components on a single chip, called a semiconductor. As a result, computers became ever smaller as more components were squeezed onto the chip.

Instead of punched cards and printouts, users interacted with third generation computers through keyboards and monitors and interfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory.


Fourth Generation (1971-Present)
After the invention of the integrated circuit, the next step in the computer design process was to reduce the overall size. Large scale integration (LSI) could fit hundreds of components onto one chip. By the 1980's, very large scale integration (VLSI) squeezed hundreds of thousands of components onto a chip. Ultra-large scale integration (ULSI) increased that number into the millions.It results in the invention of Microprocessor.

The microprocessor brought the fourth generation of computers, as thousands of integrated circuits we rebuilt onto a single silicon chip.In the world of personal computers,the terms microprocessor and CPU are used interchangeably. At the heart of all personal computers and most workstations sits a microprocessor.

In 1981, IBM introduced its personal computer (PC) for use in the home, office and schools. These minicomputers came complete with user-friendly software packages that offered even non-technical users can do an array of applications, most popularly word processing and spreadsheet programs. The 1980's saw an expansion in computer use in all three arenas as clones of the IBM PC made the personal computer even more affordable.

Computers continued their trend toward a smaller size, working their way down from desktop to laptop computers to palmtop. In direct competition with IBM's PC was Apple's Macintosh line, introduced in 1984. Notable for its user-friendly design, the Macintosh offered an operating system that allowed users to move screen icons instead of typing instructions. Users controlled the screen cursor using a mouse, a device that mimicked the movement of one's hand on the computer screen.

Fifth Generation (Present and Beyond)
Fifth generation computing devices, based on artificial intelligence, are still in development,though there are some applications, such as voice recognition, that are being used today.Artificial Intelligence is the branch of computer science concerned with making computers behave like humans.

Parallel Processing is coming and showing the possibiliy that the power of many CPU's can be used side by side, and computers will be more powerful than thoes under central processing. Advances in Super Conductor technology will greatly improve the speed of information traffic. Future looks bright for the computers.