Module Str

Integer*4, parameter :: N =1024**2
real*4,dimension(N) :: x,y,z,vx,vy,vz
integer*8, dimension(N) :: ind

end Module Str
!--------------------
Program TestRead
      use Str
      Integer*4, parameter         :: Nxxx = 8*N ! length of read buffer
      real*4, dimension(Nxxx)      :: XXX ! dummy read buffer
      Integer*8, dimension(Nxxx/2) :: III ! dummy read buffer
      equivalence (XXX(1),III(1))

iFlag =1 
   open(1,file ='Test.dat',form='unformatted')

If(iFlag ==0)Then
   Do i= 1,N
      x(i) = i    /float(N)
      y(i) = (N-i)/float(N)
      z(i) = 0.
      ind(i) = i+2048_8**3
   End Do
   Do k =1,10
      write (1) (x(i),i=1,N),(y(i),i=1,N),(z(i),i=1,N),(ind(i),i=1,N)
   End Do
Else
   Do k =1,10
      write(*,*) ' start k= ',k
      read (1) (x(i),i=1,N),(y(i),i=1,N),(z(i),i=1,N),(ind(i),i=1,N)
   EndDo
End If

write(*,'(3g12.4,3x,i11)') (x(i),y(i),z(i),ind(i),i=1,10)
write(*,'(3g12.4,3x,i11)') (x(i),y(i),z(i),ind(i),i=N-10,N)

end Program TestRead