module mod4dv 43
  implicit none
  save
  integer :: mvar ! Bit encoded model variables
  integer :: maxxy ! Bit encoded number of PEs in X and Y decomposition axes
  logical :: l4dvar ! Logical control of 3Dvar/4Dvar. Its value is
                    ! determined by the absence/presence of exchange
                    ! directory key in sufilnam 
end module mod4dv