Hi! Here is a small bug in g77's io regarding the d-format. I seems, that the d fromat is silently changed into the e format: REAL*8 T T = 1D-8 WRITE(*,'(D16.4)') T WRITE(*,'(E16.4)') T END The prog prints: 0.1000E-07 0.1000E-07 instead of 0.1000D-07 0.1000E-07 Bye, Martin.