Conversion of CDAS/Reanalysis from Cray to IBM SP/2
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CDAS/Reanalysis Project started running on a CRAY Y/MP.  Later, we 
moved to a CRAY J16.  Now, our CRAY J's have been removed and have 
been replaced by an IBM SP/2.  The conversion to the IBM was a 
major conversion as one might expect.

The CDAS/Reanalysis conversion was tested by running the systems on both 
the Cray and IBM SP/2.  For the final test, the systems were run for a 
month and the output were compared.  After successful testing, we started 
running on the SP/2 version starting with the 5/1/2000 analysis.

                             Changes

All cos-blocked files will have f77-style blocking.

In the binary files, the ibm-mainframe (S370) binary numbers will 
be replaced by single precision IEEE numbers.

In the binary files, 64-bit binary cray integers will replaced by 
4-byte integers.

In the bufr files, there will be no deviation from climatology.
(The climatology is not useful as it predates Reanalysis.)

dgn.* (monthly mean 3d flux files) will have more variables.

Optimal averaging will be discontinued.

Grib files will have f77-style headers.  (The headers speed up 
processing and are ignored by grib decoders.)

SSI will run in single-processor mode (not multi-threaded).  The SSI 
uses data differently depending on the order of the input, and the order 
is indeterminate with multi-threading, 

GRIB scaling factors of the covariances will be changed. 

The znl files will use f77 blocking and real*8 data.

Updated optimal interpolation quality control table (should have been 
done earlier).


                    Some Benefits of the Conversion

The source code to the various post-processors (spectral->pgb, 
spectral->sigma grid, spectral->isentropic) have been made portable.  
The w3lib grib routines are also portable. Source code is or will 
be made available upon request.

The reanalysis forecast model is more-or-less portable. 

The rotating archive will have more variables.

CDAS will run when the Crays are decommissioned.