Number 274 (Story #3), June 7, 1996 by Phillip F. Schewe and Ben Stein WORLD'S FASTEST COMPUTER . Scientists at the University of Tokyo have achieved the highest peak speed for a computer performing a scientific calculation: 1.08 Tflops (short for trillion floating point operations per second). With their special-purpose GRAPE-4 machine, Junichiro Makino (makino@chianti.c.u-tokyo.ac.jp) and Makoto Taiji perform simulations of the complex interactions among astronomical objects such as stars and galaxies. This type of simulation, referred to as an N-body problem because the behavior of each of the N test objects is affected by all the other objects, is particularly computation-intensive. Fortunately, two advances have made possible ever-larger simulations. One is computer speed, which is up by a factor of 100 over the past 10 years for the fastest computers. Another is improved algorithms for conducting efficient calculations. GRAPE-4 reaches its record speeds using 1692 processor chips, each performing at rates of 640 Mflops. The Tokyo researchers hope to achieve petaflops (10**15 operations per second) by the turn of the century with a suite of 20,000 processors each operating at 50 Gflops. (Computers in Physics, July/Aug 1996.)