are extremely slow at quadruple precision arithmetic.

Hardware and calculation cost
-----------------------------

For all calculations, we used GRAPE-4 ([@Taiji1996]). The GRAPE-4 is a special-purpose computer designed to accelerate the $N$-body simulation using the Hermite integrator and hierarchical timestep algorithm. The total system consists of 1692 pipeline processor chips and has the theoretical peak speed of 1.08 Tflops. The simulations reported in the present paper were performed while the assemblage and testing of the GRAPE-4 system were underway. Thus the number of processors varies during the calculation. For most of the 32k particle run, we used one quarter of the system with 423 processor chips, which has the peak speed of 270 Gflops. Calculations with smaller $N$ were performed while the available number of processors was smaller.

The actual performance depends on many factors, but most strongly on the number of particles. With the present host computer (DEC 3000/900), average speed we got for 32k-particle run was about 50 Gflops. This 32k-particle run took about three CPU months. In comparison, the 10k-particle run reported by Spurzem and Aarseth (1996) took two CPU months on a Cray YMP. Since the calculation cost of globular cluster simulation is proportional to $N^{3.3}$, one quarter 