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Hi Ryo,

Thanks for your comments. We (the Ferret developers) understand the situation and agree with your points. For several years we have been encouraging Ferret users of netCDF to solve the problems of file aggregation through the more advanced techniques offered by NcML and the Unidata TDS server. Understandably, there have been many Ferret users for whom the effort of setting up a TDS was simply more than they were willing to undertake. In order to support those users we have kept alive the Namelist-based technique for file aggregation. Despite its imperfections with respect to portability, it is effective in most cases.

With the forth-coming release by Unidata of a more complete C-based netCDF client library we are hopeful that NcML-based aggregations may become available for clients like Ferret working with local netCDF files. Until that time the Namelist-based aggregations that are offered in Ferret will remain available as a technique for those who do not want to be troubled to set up a TDS server.

   - Steve


Ryo Furue wrote:

| The $-form is an old f77 form - as far as I know. It is still
| supported but not required by some compilers, for example xlf.

Yes, you can say that it's an old F77 form, but more precisely,
it was a form that was sometimes used by SOME F77 implementations
AS AN EXTENSION.  That is, it was NOT part of the Fortran 77

This isn't a nitpicking; it's an important distinction.
If a feature was in the Fortran 77 standard, ALL compilers
that called themselves "Fortran 77" were obliged to implement
it.  The feature in question, namely namelist, was not
part of the F77 standard.  Therefore, some F77 compilers
supported it but others didn't.

There are some implications of this fact.

1) There is no guarantee that the implementations
   that currently support the $-form will continue
   to do so.  Since it was not and is not in the Standard,
   implementations are free to drop it.

2) It is highly unlikely that implementations which
   currently don't support it will do so in the future,
   because there's already a standard-conforming alternative
   (the &-form).

The same applies to any non-standard features.

Steve Hankin, NOAA/PMEL -- Steven.C.Hankin@xxxxxxxx
7600 Sand Point Way NE, Seattle, WA 98115-0070
ph. (206) 526-6080, FAX (206) 526-6744

"The only thing necessary for the triumph of evil is for good men
to do nothing." -- Edmund Burke

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