The four generations of computers

The history of computers ...

What are the four generations of computers ?

Each generation increases in reliability, speed, efficiency and ease of use and decreases in cost & size. We use computers every day this is some history behind this won amazing technology.

The first Generation (1945 - 1955)

The first generation of computers were very large computers made up of vacuum tubes and often programmed using wiring plug board. They were programmed using machine language, it was Mostly used for numerical calculations as working out mathematical tables, it also had no OS.

The Second Generation (1955 - 1965)

The second generation of computers had Mainframes made up of transistors ,at first punch cards were used to provide input, then tapes were used (for batch processing), they used assemblers and FORTRAN compilers for program writing .Simple batch processing was used with input files, programs and output on tape .Smaller computers (e.g. IBM 1401) was used to read programs and data on punch cards on to input tapes and for offline printing. Used mainly for scientific and engineering applications .FMS (Fortran Monitor System) and IBM IBSYS as OSs for handling jobs (e.g. to read a job and to run it)

The Third Generation (1965 - 1980)

The third generation of computers had Mainframes based on small scale ICs . They were Capable of multiprogramming (running several jobs at the same time) .Fixed disks were used and new jobs on cards to be executed could be read on to the disk while executing other jobs .Though the first models used multi-programmed batch processing, to cater to increased response time, timesharing was introduced later (Time-sharing Systems) .Complex OSs as OS/360 were used. They were used for various applications

including scientific and business applications. Mini computers also appeared on the market which were used by small departments , and became the platform for UNIX.

The Fourth Generation (1980 . . . )

The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip. What in the first generation filled an entire room could now fit in the palm of the hand. 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.

In 1981 IBM introduced its first computer for the home user, and in 1984 Apple introduced the Macintosh. Microprocessors also moved out of the realm of desktop computers and into many areas of life as more and more everyday products began to use microprocessors.

As these small computers became more powerful, they could be linked together to form networks, which eventually led to the development of the Internet. Fourth generation computers also saw the development of GUIs, the mouse and handheld devices.