nCUBE's Parallel I/O with Unix Compatibility

Abstract

This paper presents a parallel 1/0 facility based on an extension of Unix. This facility, both scalable and transparently integrated, is part of the upcoming release 3 of nCUBEs system software. With the addition of scalability for 1/0 as well as computing, distributed memory machines become balanced between the two functions, suiting them for a wider applications range than their traditional domain of computation-intensive tasks. The basis of the 1/0 facility is a system-level data structure called a mapping function. A mapping function describes how data from the parts of a parallel program or parallel 1/0 device are combined to form a single 1/0 stream. Combining mapping functions from senders and receivers allows the system to me an optimal communications strategy. Finally, these facilities are added as extensions to Unix. For programs with a single processor, an exact Unix environment is provided. For parallel programs, the Unix environment is extended in a natural way to accommodate parallel I/O.