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

[Christopher Smith]

On 01/9/06 06:08, "Donal K. Fellows" <donal.k.fellows at manchester.ac.uk>
wrote:

>> 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).
> 
I actually believe that in the case of '2' that the implementation should
raise a fault and not create the directory. First off, I don't believe that
any of the existing low-level batch systems will do this creation for you,
and supporting these batch systems is a primary goal of the HPC Profile.
Second, I'm not a big supporter of "implied" behaviour. That is, there is a
side-effect that a directory is created when this job is run. I'd prefer
that a user needs to make sure the directory exists if they are specifying a
working directory (using working directory seems to imply that the user
knows a fair bit about the execution environment).

As for 3, I agree. It's up to the implementation to document it's behaviour.

>> 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.
> 
Again ... I think it's up to the implementation to define it's behaviour if
the working directory isn't specified. At this point, for the HPC Profile,
I'd like to leave it at that.

-- Chris