better network filesystems

[Bob.Smart at csiro.au]

I would mention that the Grid approach is to take
network filesystems out of the kernel (where they
are a nuisance) and put them in user space. One
reason for this is that the credentials that the
user uses to access the file are something like a
kerberos ticket or a private key and matching GSI 
certificate. It is natural for user mode libraries
to access these credentials and it is much less
natural for the kernel to access them and then have 
to be careful not to use A's credential to access
a file for B. Also, of course, in the Grid the
user typically wants to use a commodity system
that is not specifically configured for him and
so it is not expected that the kernel will have
mounted the remote resources needed.

It would be nice if libc supported this better
naturally. A lot can be done with LD_PRELOAD but
it has serious difficulties (because libc internals
like to call internal entry points instead of
respecting the LD_PRELOAD ones). Parrot is a new
solution using the ptrace call:
http://www.cse.nd.edu/~ccl/software/parrot/.

Bob