A supercomputer is a computer with a high level of computational capacity compared to a general-purpose computer. Performance of a supercomputer is measured in floating-point operations per second (FLOPS) instead of million instructions per second (MIPS). As of 2015, there are supercomputers which can perform up to quadrillions of FLOPS.
Supercomputers were introduced in the 1960s, made initially, and for decades primarily, by Seymour Cray at Control Data Corporation (CDC), Cray Research and subsequent companies bearing his name or monogram. While the supercomputers of the 1970s used only a few processors, in the 1990s, machines with thousands of processors began to appear and, by the end of the 20th century, massively parallel supercomputers with tens of thousands of off-the-shelf processors were the norm.
As of June 2016, the fastest supercomputer in the world is the Sunway TaihuLight, in mainland China, with a Linpack benchmark of 93 PFLOPS (P=peta), exceeding the previous record holder, Tianhe-2, by around 59 PFLOPS. It tops the rankings in the TOP500 supercomputer list. Sunway TaihuLight's emergence is also notable for its use of indigenous chips, and is the first Chinese computer to enter the TOP500 list without using hardware from the United States. As of June 2016, China, for the first time, had more computers (167) on the TOP500 list than the United States (165). However, U.S. built computers held ten of the top 20 positions.
Supercomputers play an important role in the field of computational science, and are used for a wide range of computationally intensive tasks in various fields, including quantum mechanics, weather forecasting, climate research, oil and gas exploration, molecular modeling (computing the structures and properties of chemical compounds, biological macromolecules, polymers, and crystals), and physical simulations (such as simulations of the early moments of the universe, airplane and spacecraft aerodynamics, the detonation of nuclear weapons, and nuclear fusion). Throughout their history, they have been essential in the field of cryptanalysis.