Filesystem:/Applications/Compass.app

iOS refers to the compass internally as the magnetometer. It exists in all iPhones since the iPhone 3GS and all iPad models except the iPad (1st generation). The compass found in the iPhone 3GS is the AKM Semiconductor AKM8973, whereas the iPhone 4 and iPad 2 use the AKM Semiconductor AKM8975, the others' are not confirmed.