Os tipos de unidades conhecidas são documentados nos comentários do link :
enum fake_type {
/* Device is good. */
FKTY_GOOD,
/* Device is at least partially damaged. */
FKTY_BAD,
/* Device discards data after a given limit. */
FKTY_LIMBO,
/* Device overwrites data after a given limit. */
FKTY_WRAPAROUND,
/* Device is a sequence of wraparound and limbo regions. */
FKTY_CHAIN,
FKTY_MAX
};