n this talk, I'll summarize the current status of the GRAPE project. The goal of the GRAPE project is to develop special-purpose computers for astrophysical N-body simulations and to use them for astrophysical research. The basic idea is to develop a specialized hardware for the calculation of gravitational force between particles, and connect it to a general-purpose host computer. The specialized hardware only performs the force calculation, and all other calculations such as the orbit integration, I/O, and diagnostics are performed on the host computer. Since a large part of the computing time is spent in the calculation of the forces between particles, this approach provides us with quite significant speedup. The name GRAPE comes from "GRAvity PipE", which means the force is calculated by hardwired pipeline processors.
Since 1988, we have developed six generations of hardwares. The current machine, GRAPE-6, was completed in 2002, and has the peak speed of 63 Tflops. It has been used for simulations of, among others, planetary formation, star cluster dynamics, galaxy formation, and cosmology.
In 2004, we started the development of the next generation machine, GRAPE-DR, with planned peak speed of 2 Petaflops. In this talk, I'll overview the background ideas and development status of GRAPE-DR.
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