The environment used for testing is a ten node cluster; each a Dec Alpha 2100 4/275 machine. Each node consists of four 275 MHz Alpha processors, 256 MB of shared memory, and 4 GB of disk space between two physical disks. Each node runs Digital's OSF/1 operating system. There are two separate interconnects between nodes. The first is a standard Ethernet, and the second is Digital's Gigaswitch/ATM communications hub. Each node has a 155 Mbit/sec ATM interface (OC3c). Each disk contains a standard file-system.
At the time of testing, node ten was not used for testing since it was running a beta copy of Digital Unix 4.0, and was unstable. Nodes one through six were actually connected to the atm switch, and all nodes were connected to the Ethernet.