How does it work?
Through the S.M.A.R.T. system, hard disk drives incorporate a suite of advanced diagnostics that monitor the internal operations of a drive and provide an early warning for many types of potential problems. When a potential problem is detected, the drive can be repaired or replaced before any data are lost. The S.M.A.R.T. system consists of software that resides both on the disk drive and on the computer. The software on the disk drive monitors the internal performance of the motors, media, heads, and electronics of the drive. The computer software (Active SMART) analyzes the drive's internal parameters and warns the user about all changes of drive's health status.
not trying to sound mean here , but
BACK UP YOUR STUFF!!
good luck