To obtain the source code from the ftp site, change directory to the osm-htessel directory and retrieve the latest source code (filename may be different than shown):
Sample session
% ftp ftp.ecmwf.int
user: openifs
cd src/osm-htessel
ls
get surf_CY40R1_control.tar.gz
bye
% tar zxf surf_CY40R1_control.tar.gz
The tarfile unpacks into a directory containing the following files (some differences may exist between versions):
% ls
compile_fcm.ksh surf
compile_fcm.ksh -- this is a script used at ECMWF to compile the OSM. It is provided for guidance only and cannot be used external to ECMWF without modification.
surf -- this directory contains all the source code and compilation scripts.