At LLNL we plan to have a single MPI-IO library that can access
files in both PIOFS and HPSS file systems.
Other sites will also want similar capabilities.
Any way, the problem still exists even when MPI-IO accesses only HPSS files.
The problem is that HPSS has its own chdir-like routine.
Executing the standard unix chdir function doesn't change HPSS's
notion of what the current working directory is.
In general, different file systems on the same platform may have
different ways of doing chdir-like things.
Would it make sense to add chdir/mkdir/rmdir functionality to the MPI-IO spec,
in order to have a consistent way to do this for different file systems?
If not, one could rely on the use of full path names
(though this is somewhat undesirable for performance),
or on the application program using the several file-system-specific
versions of chdir (thus allowing relative path names in MPI_Open).
_____________________________________________________________________________
Robert Kim Yates (510) 423-5535 rkyates@llnl.gov
Scalable I/O Facility
Lawrence Livermore National Laboratory