Version 1.0 has a very weak I/O system. There reason for this. In order to maintain portability, we have restricted I/O in version 1.0 because there are, as yet, no standard mechanisms to address parallel file system calls on all the platforms we wish to support. We are working on defining a standard parallel extension to the streams package, but that will take a while.
For Version 1.0, output to stdout can go anywhere but input from stdin and any other file I/O is restricted to the main thread.