First Generation (1940-1956) Vacuum Tubes
The IBM 650 Magnetic Drum Data Processing Machine was a first-generation computer. Frank Hamilton was the principal designer of IMB 650.
The 650 is a vacuum-tube logic, drum-memory, decimal — not binary computer. Data is stored in words containing ten decimal digits and a sign, and instructions operate on numbers stored in this format. IBM called the 650 an automatic calculator, not a computer:
“One of the most exciting achievements of our generation is the development of the electronic automatic digital calculator. Although any schoolboy can perform any operation done by the calculator, the speed and economy with which the calculator does them are so great that automatic calculation is revolutionizing large areas of science, engineering, business, industry, and defense. A single giant calculator can do more arithmetic than the entire population of the United States could do with pencil and paper”
Second Generation (1956-1963) Transistors
The IBM 7090 was a second-generation computer was a transistorized version of the vacuum-tube-logic 709 and the first commercial computer with transistor logic. The 7090 was intended mainly for scientific computing, but it was also suitable for business and administrative use.
Third Generation (1964-1971) Integrated Circuits
The IBM 360/91 was a hybrid of second- and third-generation computer. It was specifically designed to handle high-speed data processing for scientific applications such as space exploration, theoretical astronomy, subatomic physics and global weather forecasting. IBM estimated that each day in use, the Model 91 would solve more than 1,000 problems involving about 200 billion calculations.
Fourth Generation (1971-Present) Microprocessors
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 1981IBM 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 GUI (Graphical User Interface), the mouse and handheld devices.
Fifth Generation (Present and Beyond) Artificial Intelligence
The Fifth Generation Computer System (FGCS) seem to be VLSI architecture, parallel processing such as data flow control, logic programming, knowledge base based on relational database, and applied artificial intelligence and pattern processing. Inference machines and relational algebra machines are typical of the core processors which constitute FGCS.