Currently, the fastest supercomputer in the world is Blue Gene/L built by IBM.
In March 2005, Blue Gene broke its previous speed record of 70.72 teraflops, (70.72 trillion calculations per second) reaching 135.5 teraflops.
It is thought supercomputers could soon be as powerful as the human brain - some scientists believe our brains can carry out around 10,000 trillion operations per second.
IBM currently plans to finish building another supercomputer called Blue Gene/P in 2006.
Its expected to be the first supercomputer to break one petaflop, or one quadrillion operations per second.