A hard-disk drive (HDD) is described. During operation of the HDD, measured internal temperatures in the HDD may be stored in a first table, and state information specifying operational states of the HDD associated with ranges of internal temperatures may be stored in a second table. Note that a given operational state in the second table may be associated with a corresponding internal temperature in the first table. Furthermore, during operation of the HDD, the first table and/or the second table may be stored on: a rotatable medium in the HDD, a semiconductor memory in the HDD, or both. This stored table information may facilitate error detection and diagnosis.