Programs written for the iPSC/860 are based on the control parallel model. In control parallel programs, each processor independently executes its version of the program on its own data and may communicate with other processors from time to time. The programmer controls the distribution of the data to the nodes and also specifies the task to be performed by each node.
There are two different methods for control parallel programming on the iPSC/860, namely, host/node programs and hostless programs. Hostless programming is the recommended method because it is sufficient to write a single program that will execute on all the processing nodes. In the host/node programming model, the host program is distinct from the node program.