DFC is a utility to convert data files to/from the non-standard entry format. DFC FILE.DAT/NU:N is equal to conversion to standard: READ(1,*)(A(I),I=1,N) DO 10,I=1,N 10 WRITE(2,*)A(I) DFC FILE.DAT/RE[:N] is equal to conversion from standard: DO 10,I=1,N 10 READ(1,*)A(I) WRITE(2,*)(A(I),I=1,N) NOTICE [:N] is optional but :N is NOT optional N < 4096