SMART resides between the basic input/output system (BIOS) and hard drive and works on drive faults that occur due to age and/or mechanical wear and tear. SMART may detect faults after evaluating bad sectors on the drive’s physical surface, the drive head and other mechanical parts.

Based on the level of wear and tear, SMART can predict a drive's remaining lifespan, which allows a user to back up data and/or replace the drive. However, SMART is unable to detect sudden or accidental failures, such as electronic component failures or physical manhandling.