Generations of Computer

First Generation Computers:
It was the period of world war which gave rise to the age of computers. The most important computers were (ENIAC) and (UNIVAC 1). ENIAC stands for Electronic Numerical Integrator and Computer. John Presper Eckert and John W played an important role in development of this program. ENIAC consisted of 7000 resistors and 18000 vacuum tubes. ENIAC was a decimal rather than a binary machine. It means that its numbers were represented in decimal form and arithmetic was formed in decimal system. Furthermore, UNIVAC 1 was designed by Remington Rand in 1951 and it stands for Universal Automatic Computer. Lastly the most important feature of the first generation computers were that it used the vacuum tubes and magnetic drums.
Advantages of 1st Generation Computers:
• Vacuum tube technology made possible the advent of electronic digital computers.
• Vacuum tubes were the only electronic components available during those days.
Disadvantages of 1st Generation Computers:
• Too bulky in size.
• The major drawback of ENIAC was that it had to be programmed manually by setting switches and lugging and unplugging cables.

                                             
                                                          Vacuum tube
Second Generation Computers:      
Transistors were invented in 1947 by William Shockley, William Brattain and John Bardeen. The invention of transistor marked the start of second generation. The major change in computers was the replacement of vacuum tubes with transistors. As compared to first generation computers, second generation computers were smaller and of high speed. Moreover, the Instructions could be stored in internal memory of the computer and theses computers replaced machine language with the assembly language. Furthermore, it used low and high level languages such as COBOL and BASIC etc.
Advantages of 2nd Generation Computers:  
• Much less expensive than a vacuum tube.
• A transistor can...