The iPSC/860 is a multi-user, multi-programming system. Each node on the iPSC/860 runs the NX/860 operating system. The host runs the UNIX operating system.
The iPSC runtime environment consists of a set of system commands that you can use at the shell prompt from the host and a set of system calls that you can use in node programs. It is important to note the difference between system commands and system calls. The system commands are part of the iPSC system UNIX extension. The system calls on the node are part of the NX/860 operating system.
Each user program runs on all the nodes of a hypercube of specified dimension. The user can specify a sub-hypercube of dimension ranging from 0 to the maximum available. A user can also run several different programs, each on a distinct hypercube.