HDD are predicted to be the major means of information storage for the foreseeable future, especially given the explosive development of cloud storage. Our models provide important fundamental information relating to recording processes, especially the physics of Heat Assisted Magnetic Recording (HAMR). HAMR requires the heating of the magnetic storage medium through the magnetic phase transition at rates approaching a billion Degrees per second: a situation suitable only for the most advanced models. Our VAMPIRE code is used by Seagate Researchers in Fremont, California, to study advanced designs for HAMR media. We are also working closely with the Seagate R&D centre in Northern Ireland to develop models of spin transport in advanced sensors used to detect the written bits during the read back process.