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FCM - used to build and compile the model. FCM is available from the OpenIFS ftp download site. FCM is developed by the UK Meteorological Office. For more information, please visit: FCM home page. Note that FCM may need additional Perl modules installed. Check the FCM install page for more details.
grib-api - this is available from the OpenIFS ftp download site. Although this is also available from the ECMWF software download page, it's recommended the one provided on the ftp site is used as it will have been tested and known to work with OpenIFS. See the grib_api install page for more details on how to build grib_api for OpenIFS.