Second Generation Computers

The invention of semiconductor transistors by the three physicists John Bardeen, Walter Brattain and William Shockely at Bell Laboratory had made big revolution in the fields of electronics.The transistors replaced the vacuum tubes of the first generation computer.The use of such transistors marked the arrival of the second generation computers in the world.The transistors were made of germanium semiconductor material.They were small,faster and reliable.These transistors had no filament(to burn like vacuum tubes)hence, they did not generate heat and could handle much lower power.The invention of magnetic cores memory made possible to replace delay line memories as the internal storage medium(random access memory).Magnetic cores were tiny rings made of ferrite It could be magnetized either in clockwise (i.e. to represent 0) or anticlockwise direction (i.e. to represent 1).Magnetic core memories were small in size hence the internal storage capacity of second generation computers increased whereas the size was reduced.
Paper tapes and punch cards were used for auxiliary storage or external storage.During this period, magnetic tape and magnetic disk were also developed.The magnetic disk had additional advantage.The direct access capability of magnetic disk made it possible to go to the desired memory location of data without going through the previous locations of data.
As a result of these improvement the second generation computers become smaller, faster and they could store large numbers of data compared to the previous generation.
Example of second generation computers area as follows:
Nation Cash Register model no. 315, IBM 1401, Control Data Corporation 1604,6600,General Electric Corporation  635,200