The second generation of computers came about thanks to the invention of the transistor, which then started replacing vacuum tubes in computer design. Transistor computers consumed far less power, produced far less heat, and were much smaller compared to the first generation, albeit still big by today’s standards.
The first transistor computer was created at the University of Manchester in 1953. The most popular of transistor computers was IBM 1401. IBM also created the first disk drive in 1956, the IBM 350 RAMAC.