Q27. How are the computers of four different generations superior as compared to their previous models?
Ans. First Generation Computers (1949-55)
The first generation computers used thermionic values (vacuum tubes) and machine language was used for giving instructions. The first generation computers used the concept of ‘stored program’. The computers of their generation were very large in size and their programming was a difficult task.
The first generation computers suffered from some ‘big’ limitations like slow operating speed, restricted computing capacity, high power consumption, short mean time between failures, very large space requirement and limited programming capabilities.
Further researches in this line aimed at removal of these limitations.
Second Generation Computers (1956-65)
A big revolution in electronics took place with the invention of transistors. Transistors were highly reliable compared to tubes. They occupied less space and required only 1/10 of the power required by tubes. Also they took 1/10 time (switching from 1 to 1 or 1 to 0 ) needed by tubes and were ten times cheaper than those using tubes.
Another major event during this period was the invention of magnetic core for storage. Magnetic cores were used to construct large random access memories. These new developments made these computers much more reliable and paved the way for the development of high level language (HLL).
With speedy CPUs and the advent of magnetic tape and disk storage, operating systems came into being.
Third Generation Computers (1966-75)
The third generation’s computers replaced transistors with ‘Integrated Circuits’ known popularly as chips.
The third generation computers using integrated circuits proved to be highly reliable, relatively inexpensive, and faster. Less human labor was required at assembly stage.
Fourth Generation Computers (1976-present)
The advent of the microprocessor chip marked the beginning of the fourth generation computers. The emergence of the microprocessor (CPU on a single chip) led to the emergence of extremely powerful personal computers. Computers costs came down rapidly. The faster accessing and processing speeds and increased memory capacity helped in development of much more powerful operating systems.