Wound magnetic strips would get wiped by all the immense magnetic fields you encounter in your space travels. What is needed is a robust medium not dependent upon magnetic field moment. How about, urm, an inert medium - paper for example, with holes punched into them in a pattern readable by physical sensors on some form of machine? Alternatively, how about a disk-like object that can have an information pattern inscribed on it, perhaps using a helical encoded path using height-mapping for levels of analogue data?