function mav_file_source,def_source if keyword_set(def_source) then source = def_source else begin source = file_retrieve(/struc) source.remote_data_dir = 'http://sprg.ssl.berkeley.edu/data/' if file_test(source.local_data_dir+'maven/.master',/regular) then source.no_download =1 ; source.no_clobber = 1 ; safety net for now source.verbose=2 source.min_age_limit=300 ; source.no_clobber=1 ; source. endelse return,source end