(j3.2006) [MPI3 Fortran] Feedback from Fortran J3 meeting

[Keith Bierman]

On May 30, 2008, at 1:46 PM   5/30/, Van Snyder wrote:

>
>
> It was at the February 1997 meeting at the Sunrise Suites, at which I
> proposed to allow user hooks into the I/O process in paper 97-114.  I
> gave several reasons for wanting to allow users to process I/O at the
> lowest level, including MPI/PVM.
>
>> I/O tends to be pretty slow; on the other hand exposing the inner
>> workings of the I/O library is often an exercise in pain (and might
>> constrain future internal evolution).

Then I think the issue was the complexity of imposing "imposability"  
on existing implementations (many of which were considerably more  
complex than the Univac V library. Indeed, JPL even  had their own  
NAMELIST implementation at one point ... I recall working in the lab  
late one night when the author was tweaking it (Dan, last name I've  
forgotten, who had gone blind by that time ... it was amazing how he  
could keep page after page of code in mind, make changes via a semi- 
literate high school assistant :>)
>
> For purposes of the present discussion, it could be limited to
> unformatted I/O, or described in a form that makes it clear that

Even imposing upon unformatted I/O might be complex on some kinds of  
systems (variations of memory mapping, multi-processors with  
dedicated "I/O" units).

-- 
Keith H. Bierman   khbkhb at gmail.com      | AIM kbiermank
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