The pla85900 computations were carried out on clusters of Intel Xeon and AMD Opteron compute nodes at the School of Industrial and Systems Engineering at Georgia Tech. The Intel cluster consits of 96 nodes, each equipped with dual Xeon 2.8 GHz processors and 2 GBytes of memory. The AMD cluster has 32 nodes, each with dual 2.4 GHz AMD Opteron 250 processors and 4 GBytes of memory. The nodes are networked using switched 100 MBit ethernet.