Supercomputers are the fastest, most expensive and biggest usable computers. They can be classified into three groups. Commodity supercomputers that use off-the-shelf processors, which are less expensive and used more in industry, scientific supercomputers, which are more expensive but have better performanse. There is also hybrid supercomputers that take advantage of both supercomputers. The first supercomputer was made by Seymour Cray and it was named CDC 6600. He is one of the most influential people in supercomputers field because he dictated with supercomputer market for one decade. Supercomputers are based on computers and because of that they inherited their limitations and disadvantages. One of the biggest problems is the overheating of supercomputers which are now solved in different ways. Supercomputer software is specially developed to help supercomputer use its full potential. Supercomputers usually use Linux operating system if they are using commercial operating system but strongest supercomputers usually have their own operating system. Supercomputers are widely used, from defense and intelligence to astronomy and transportation. The future of supercomputers is seen in optical and quantum computer which are currently still not sufficiently developed to able to produce.