[jsdl-wg] DataStaging concerns

[William Lee]

>
> Actually, Source and Target *are* specified in each DataStaging  
> element, if applicable.
> From the viewpoint of the consuming service, the Source child of a  
> DataStaging means something like "from URL" (to fetch from that URL  
> in stage in), and the Target child of a DataStaging respectively  
> means in deed something like "to URL" (to store at).
> In fact, the element names could be something different (i..e.  
> "FetchFrom" and "StoreAt"), but then they may confuse other people.  
> That's how standards are like, I presume. :o)
>
> Cheers,
> Michel
>

Taking the view from the thread, I'll try to make the meaning of  
<Source/> and <Target/> more precise. The consuming system will  
ensure the file identified <FileName/> will have its content  
originate from the source url, not necessarily fetched, it might be  
mounted / copied / cached. For <Target/>, the post-condition after  
the job is finished is that the file resource at the target URL will  
be identical to (or appended from) the file content on the execution  
system. The file might be staged-out *after* the job, or streamed  
during the job, the only guarantee is it will be available after the  
job has finished.

I think the dilemma in pinning down the semantic of DataStaging is  
because JSDL does not imply the consuming system must be a job  
execution system. Even talking about "after the job is finished"  
might assume too much in the context of JSDL.

William



--- William Lee @  London e-Science Centre, Imperial College London --
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