Supercomputers are extremely powerful computers used for complex calculations. The document discusses the history of supercomputers from ENIAC in 1946 to current systems exceeding 100 petaflops. Supercomputers run on Linux/Unix and must be cooled due to large heat output. They are used for weather modeling, climate research, materials science and nuclear weapons simulation. The fastest is Sunway Taihulight in China with over 10 million cores. Pakistan's fastest is at NUST with over 30,000 cores and used for research.