Parallel input/output (I/O) is an important, but often neglected aspect of high performance computing. The authors of this paper provide a clearly written overview of the various aspects involved in establishing good I/O performance of parallel applications. They provide a number of clear examples of how to obtain good I/O performance by using message passing interface (MPI) I/O.

The only small criticism I have is that past, present, and future are sometimes intermingled in the text. Although it is very useful to know how things have come together historically in the I/O world, it is of less interest when you just want to know how to program the I/O in your application. A clearer separation would improve the readability of the chapter. Nevertheless, the chapter on I/O brings useful insight and many references to the world of high performance I/O.