A storage management device (5, 12) is intended for managing data storage areas (DSB) of a mass storage, such as a hard disk (5), for example,. Associated data storage areas (ID1, ID2, ID3) of the mass storage are concatenated by concatenation data (VD). The storage management device (5, 12) contains backup means (12) in order to determine backup data (SD), before overwriting the concatenation data (VD) with modified concatenation data (GVD), the backup data (SD) identifying the modified concatenation data (GVD) to be stored on the mass storage. If the process of storing the modified concatenation (GVD) is unexpectedly interrupted, the storage management device (5, 12) is designed to determine valid concatenation data (VD, GVD).