Some information from the mailing list. Consider these as proposals:

WRT (1) Navigation rules

Marvin and Donnal seen to agree on ...

"As I said, forbidding ".." from anywhere in *any* path in a HPC-profiled JSDL document would be reasonable, and forbidding interoperable jobs from 
doing a chdir() or equivalent at all is also reasonable..."

WRT (2) Write permission (ROOT system in particular).

No real discussion, but mostly this should be out of scope. The use of this abstraction is for "identification". Access rights are dependent on many 
othere things. E.g. I should be able to write to my home directory, even when it is "identified" by /users/daves.

WRT(3 & 4) Sharing/consistency model, particularly for TMP on a cluster and Data lifetime

Discussion still needed, but the identified directories seem to be:

From Donnal and agreed to by Marvin:

The best way forward is probably to just define a small set of VFSes that should/must be supported. That will scope the interop problem nicely. I think (based on UNICORE experience) that the key locations for a job are:

   Working Directory - main place for the job to work; may be isolated from other jobs (though that's really a quality-of-service feature that will be good for some jobs, bad for others, and 
neutral for the rest)

   Fast Local Temporary Directory - basically /tmp on Unix; need not be shared across a cluster; no isolation guarantees

   Large Temporary Directory - place for things like staged in BLAST databases, intermediate weather model dumps, etc. Should be shared across the 
cluster, should have a longer-term delete policy than /tmp if different from it. May be the same as FLTD;  no isolation guarantees

   User's Home Directory - for application settings, definitely long term persistence (backups strongly recommended!) but might not permit very large 
files. Definitely possible to access outside the scope  of the job. Need not be isolated from other jobs, and isolation  from other users is dependent
 on user and site policy.

In theory, all could be the same directory, but that would be very odd.

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ROOT was originally included, but there was some discussion that it was not univeral enough. To be discussed.