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

[Donal K. Fellows]

Andreas Savva wrote:
> I've had a look through the document; here are some comments:

I'm answering these as I understand them. Points I don't answer are ones
where I'd just be agreeing with Andreas. :-)

> 2. Executable is defined as a mandatory element in the same way as in
> the JSDL PosixApplication. Given the discussions we've had in the
> context of the EMS Scenarios this should probably be optional (0-1)
> since the location may not be known until deployment is finished. (This
> isn't an issue for the HPC profile.)

Perhaps the right thing to do would be to leave it optional in this spec
and then profile it to be mandatory in the HPC Profile. The advanced
cases we were considering today lie outside the scope of the HPCP, but
this spec is still quite possibly useful for them.

> 3. Donal changed the Argument type from normalizedstring to string. If I
>  recall correctly there was a very long and heated discussion around
> this in the past (but, happily perhaps, I can't recall details). Could
> someone who was involved in the definition of this element followup?

The difference is that xsd:normalizedString trims spaces and xsd:string
does not. For arguments, it is sometimes necessary to have leading or
trailing spaces. Occasionally, you even need args that are nothing but
whitespace. What this spec is supposed to do is to indicate that
whatever the implementation does, it must get the argument quoting right
so that (near[*]) arbitrary arguments can be given.

> 4. Working directory - In contrast to Donal's comment I think if this is
> not present it should not be created.

If the user doesn't give a working directory, it's up to the implementor
to do some default way of handling this. Some systems will want to do
this by running in the home directory, and others will want to create a
new per-job directory. The only files that the user should count on
being there are those that they have staged there themselves. (If the
user does not specify any stagings, they must obviously not be relying
on any relatively-named files at all. Their choice.)

Whatever the implementor does, they should document what they do in that
case. The HPC Profile may wish to restrict this. (I'd recommend that
they do just that!)

> Btw, I am really curious here, how is a user going to specify that they
> want a job to run in their home directory, wherever that place may be?
> Surely the exact location may differ from machine to machine.

This spec (and more particularly the HPC Profile) isn't about defining
portable jobs anyway. After all, requiring an executable pathname isn't
even close to portable, and nor is there any mechanism for dealing with
differences in path separator between platforms. (At least nobody is
trying to suggest that MacOS 9 should be used as a HPC platform; the
directory separator scheme there was *much* different...)

> 5. Why was GroupName dropped?

Not portable to non-POSIX platforms I think.

Donal.
[* You'd still be limited by the XML 1.0 spec, and there's the whole
    separate business of understanding the character encodings actually
    used. Perhaps the spec should say something there, since it is likely
    that just copying the bytes from the input document won't work. ]