[MITgcm-support] Changing mds file suffix

[Jean-Michel Campin]

Hi Jody,

It should not be too difficult to support a different convention for 
output file suffix, but probably easier if we keep the 10 digits/character.

One issue with "time in second" suffix is that it does not support time-step
that are not integer number of seconds, and after 320 something years
it exceeds the 10 digit number limit.

And regarding meta files, time is included in the list of arguments of the routine
that write meta files (S/R MDS_WRITE_META in file mdsio_write_meta.F),
and some *.meta files contain time information ( timeInterval = ...),
such as pickup files and output files from pkg/diagnostics.
But most of the I/O routines in pkg/rw and/or in pkg/mdsio don't have
myTime as argument and consequently output meta files that are written from
there don't have any time information.

Cheers,
Jean-Michel

On Sun, Feb 26, 2017 at 08:35:35PM -0800, Jody Klymak wrote:
> 
> Hi all, maintainers in particular,
> 
> There are a number of places in the code where file i/o creates a suffix based on myIter:
> ```
> WRITE(suff,'(I10.10)') myIter
> ```
> 
> I???ve found this restrictive for runs where I need to change deltaT (i.e. slow spinup past a startup transient).  I need to rename pickup files, and, worse, previous output can have the same iteration number as new output and get overwritten.  I???d *prefer* to save my files as 
> ```
> WRITE(suff,'(I10.10)') myTime
> ```
> i.e. `T.0000036000.data` refers to 10 hours, rather than iteration 36000.
> 
> Would it be possible for me to change the code above to:
> 
> ```
> CALL RW_GET_SUFF( myTime, myIter, myThid, suff )
> ```
> 
> and write that code with the default set to the above, but new parameters that allow other formats?  (i.e. I could imagine some would like simulation hours or days).  
> 
> Is this a terrible idea for some reason?  If I went through the exercise, would it have a hope of being merged?  I???d just do it for myself, but its actually deep enough in the code that it would be a personal nuisance to repatch every new version that I download.
> 
> I guess while I???m at it, I???ll ask again why the meta files don???t have the time written in them.  Is there anything that would break by adding:
> 
> ```
> timeStepNumber = [       8640 ];
> myTime = [     43200 ];
> ```
> 
> Thanks a lot,  Jody
>      
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