Major Changes in Version 1.0.3

• When used with MPICH 1.2.1, the MPI-IO functions return proper error codes and classes, and the status object is filled in.

• On SGI's XFS file system, ROMIO can use direct I/O even if the user's request does not meet the various restrictions needed to use direct I/O. ROMIO does this by doing part of the request with buffered I/O (until all the restrictions are met) and doing the rest with direct I/O. (This feature hasn't been tested rigorously. Please check for errors.)

  By default, ROMIO will use only buffered I/O. Direct I/O can be enabled either by setting the environment variables MPIO_DIRECT_READ and/or MPIO_DIRECT_WRITE to TRUE, or on a per-file basis by using the info keys direct_read and direct_write.

  Direct I/O will result in higher performance only if you are accessing a high-bandwidth disk system. Otherwise, buffered I/O is better and is therefore used as the default.

• Miscellaneous bug fixes.