Second Generation ( 1956-1963 ) Transistors

Transistors replaced vacuum tubes and ushered in the second generation of computers. The transistors was invented in 1947 but did not see widespread use in computers until the late 1950s. The transistors was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation prodecessosrs. 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 still relied on punched cards for input and printouts for output.

Second-generation computers moved from cryptic binary machine language to symbolic, or assembly, languages, which allowed programmers to specify instructions in words. High-level programming languages were also being developed at this time, such as early versions of COBOL and FORTAN. These were also the first computers that stored their instructions in their memory, which moved from a magnetic drum to magnetic core technology.

The first generation computers of this generation were developed for the atomic energy industry.