[jsdl-wg] Re: [ogsa-hpcp-wg] Minutes for OGSA HPC Profile telecon (Aug 18 2006)

[Donal K. Fellows]

Andreas Savva wrote:
> I still can't remember the discussions on this but I believe this was
> the reason we allowed empty argument elements and said they must not be
> collapsed. The question I have if you change the argument type to a
> string is then why do you need multiple argument elements?
> 
> Also I don't have a big problem with restricting definitions (e.g., by
> removing the filesystem attribute in this application extension) but I
> do have a problem with changing types for identically named elements.

I've tried looking up the word "collapsed" in relation to XML, and it
seems to be fairly meaningless. Instead, these things are best defined
in terms of XSD facets, and given the general requirements (no trimming,
no internal replacement of whitespace sequences, no processing at all)
xsd:string is the exact type we need. If the main JSDL spec says
anything else, I think we can say that it's in error. :-)

> Donal, are you saying that if the directory is not present it should be
> up to the implementation to decide what to do? I read your comment as
> saying that the specification should state that the directory should be
> created.

There are 3 cases:
  1: User specifies existing directory - must not be created!
  2: User specifies non-existing directry - must be created!
  3: User does not specify directory. This case is up to the implementor
     but will probably follow one of the two patterns:
    3a: Use existing "well-known" directory, e.g. $HOME. Implementation
        must document what directory will be chosen.
    3b: Create new directory with "random" name so that jobs are
        isolated. Implementation must state that this will happen.

I do not believe that the behaviour of all existing batch systems is the
same in case 3 FWIW; lower-level ones will tend to 3a (as it assumes
less) and higher-level ones will tend to 3b (as it isolates better).

> Yes, but it is still a common use case to run a job with 'home' being
> the working directory, or in a subdirectory relative of home. I think a
> way to specify that without giving the full path name isn't too much to ask.

Not sure I agree. The HPC Profile stuff is for a very restricted case.

Donal.