!
!------------------------------------------------------------------
MODULE   setInitialConditions
PUBLIC
Character (LEN=12), DIMENSION(4) :: NamesDir=(/ &
       'PMstrtXX.DAT','PMstrtVX.DAT',&
       'PMstrtYY.DAT','PMstrtVY.DAT'/)

      Integer*4, PARAMETER :: NGRID = 1024       ! zero-level mesh in 
      INTEGER, PARAMETER :: NPAGE = 1024**2,  & ! # particles in a record
                            NRECL = NPAGE*6 ! # particles in a record
      Real*4, dimension(NPAGE)             ::  xbuf,vxbuf
      Integer*4, PARAMETER :: nbyteword = 4      ! defines length of direct-access:1or4

end MODULE setInitialConditions
!------------------------------------------
      
Program TestIO
use setInitialConditions
  Npages = 128
  NBYTE = NPAGE*4
  NACCES= NBYTE / nbyteword

       OPEN(31,FILE=NamesDir(1),ACCESS='DIRECT',form='unformatted', &
                         STATUS='UNKNOWN',RECL=NACCES)  ! x coord and veloc
       OPEN(32,FILE=NamesDir(2),ACCESS='DIRECT',form='unformatted', &
                         STATUS='UNKNOWN',RECL=NACCES)  ! y
       OPEN(33,FILE=NamesDir(3),ACCESS='DIRECT',form='unformatted', &
                         STATUS='UNKNOWN',RECL=NACCES)  ! x coord and veloc
       OPEN(34,FILE=NamesDir(4),ACCESS='DIRECT',form='unformatted', &
                         STATUS='UNKNOWN',RECL=NACCES)  ! y
Do i=1,NPAGE
   xbuf(i) = i
   vxbuf(i) = Npage-i
EndDo   
         Do i=1,Npages
          write(*,'(10x,a,i5,a,4i11)')' Test Reading=',i
          !write(33,rec=i)xbuf
          !write(34,rec=i)vxbuf
          read(33,rec=i)xbuf
          read(34,rec=i)vxbuf
         end Do

       
     end Program TestIO