Fortran Binary files opening

[Angel Bongiovanni <abongiov@xxxxxxx>]

Hello !

I have a Fortran77 compiler running on a Sunspst2.
Additionally, I have a common binary file (coming from
a .fits image --> binary file via IRAF package facilities).
This file has about 8.3 MB.

To make a proof,  I have this elemental section of program:

--
        program for O.P. spectra from bin files

        implicit integer*4 (i-n), double precision (o-z, a-h)
        open(unit=1,access='direct',file='obs12.b',
     *  form='unformatted',status='old')

        do i=1,5000000
        read (1) counts
        write (6,*) counts
        enddo
100  close(1)
        end
--

Running this, the compiler quits with a core dumped.
Does somebody can help me with the correct keys in the opening line ?

Thanks in advance,

Angel Bongiovanni