THE PCI INTERFACE FOR GRAPE SYSTEMS - PCI-HIB

We developed a PCI interface for GRAPE systems. GRAPE (GRAvity piPE) i s a special-purpose computer for gravitational N-body simulations. A G RAPE system consists of GRAPE processor boards and a host computer. GR APE processors perform the calculation of gravitational forces between particles. The host computer performs the remaining calculations. The newest of the GRAPE machines, GRAPE-4, has achieved a peak performanc e of 1.08 Tflop. The GRAPE-4 system uses TURBOChannel for the interfac e to the host, which limits the selection of the host computer. The TU RBOChannel bus is not supported by any of recent workstations. We have developed a new host interface board which adopts the PCI bus instead of the TURBOChannel. PCI is an I/O bus standard developed by Intel. I t has a fairly high peak transfer speed, and is available on a wide ra nge of computers, from PCs to supercomputers. Thus, the new interface allows us to connect GRAPE-4 to a wide variety of host computers. In t est runs with a Barnes-Hut treecode, we found that the performance of the new system with the PCI interface is 40% better than that of the o riginal system.