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.

History of Computers

The history of computers starts out about 2000 years ago, at the birth of the abacus, a wooden rack holding two horizontal wires with beads strung on them. When these beads are moved around, according to programming rules memorized by the user, all regular arithmetic problems can be done.Another important invention around the same time was the Astrolabe, used for navigation.

Blaise Pascal is usually credited for building the first digital computer in 1642. It added numbers entered with dials and was made to help his father, a tax collector. In 1671, Gottfried Wilhelm von Leibniz invented a computer that was built in 1694. It could add, and, after changing some things around, multiply. Leibniz invented a special stepped gear mechanism for introducing the addend digits, and this is still being used. The prototypes made by Pascal and Leibniz were not used in many places, and considered weird until a little more than a century later, when Thomas of Colmar created the first successful mechanical calculator that could add, subtract, multiply, and divide.

Computer and Babbage
While Thomas of Colmar was developing the desktop calculator, a series of very interesting developments in computers was started in Cambridge, England, by Charles Babbage, a mathematics professor. In 1812, Babbage realized that many long calculations, especially those needed to make mathematical tables, were really a series of predictable actions that were constantly repeated. From this he suspected that it should be possible to do these automatically. He began to design an automatic mechanical calculating machine, which he called a difference engine.

Babbage continued to work on it for the next 10 years, but in 1833 he lost interest because he thought he had a better idea — the construction of what would now be called a general purpose, fully program-controlled, automatic mechanical digital computer. Babbage called this