Why are second generation computer (1956-1963 important?
Transistors replaced the vacuum tubes and ushered in the second generation of computers. The transistor was invented in 1947, but was not widely used in computers until the late 50s. The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation predecessors. Though the transistor still generated a great deal of heat that subjected the computer to damage, it was a vast improvement over the vacuum tube.
Second generation computers allowed programmers to specify instructions in words. High-level programming languages were also being developed at this time, such as early version COBOL and Fortran. These were also the first computers that stored their instructions in their memory, which moved from a magnetic drum to magnetic core technology.