Hard Disk Sentinel analyses the S.M.A.R.T. attributes provided by the disk and by evaluating these values, creates and displays a textual rating. It may contain the number of problems encountered during the lifetime of the hard disk, the spin up problems, the data transfer errors, etc. The background color of this area (green, yellow, red) indicates the health of the disk. The text area may contain tips to correct the problems so it is recommended to read the details.
What is a “bad sector”? How they born and how they can be fixed? Users are confused because verifying the disk surface with software (for example by using Windows Scandisk) does not report any problems or bad sectors.
S.M.A.R.T. is constantly analysing the disk surface during normal operations. If it finds a problemmatic area (one or more sectors where the data is hard is hard to read or write), it tries to read the data and copy it (reallocate) to the spare area. The original location is then (internally) marked as bad and all further read/write operations pointing to the original location is then redirected to the spare area.
When the operation is completed, the original (bad) area is not accessible by software any more. Even re-install or complete re-format will not show problems because the original bad area is not used any more. That’s why software (for example Windows’ Scandisk) will not find problemmatic sectors. Only the hardware security erase function will access this area (clearing these sectors also).
That’s why for example DOS “format” command will never show bad sectors on most modern hard disks because of S.M.A.R.T. (except if the spare area is full but it is really hard to find a such hard disk).
Reallocation of the sectors may be completed with or without some errors (hard disks are working much better now compared to older models). But the reallocation procedure may cause system instability if it takes too much time.
The user should not notice anything about the steps described above – just when the number of bad sectors is high enough (the threshold is reached) and then S.M.A.R.T. predicts a possible failure.
A very small scratch or mote on the disk surface can cause some bad sectors. Usually, if the number of bad sectors is low, they do not cause big problems. But if their number is constantly increasing (and the displayed health value is decreasing), these can lead to failure. It is recommended to monitor your hard disk constantly if your hard disk is not 100% perfect.
Test Hard Disk
Si consiglia periodicamente di analizzare e verificare lo stato del disco (specialmente se il suo stato di salute è inferiore al 100%). Il metodo migliore è di eseguire un Extended self-test, che analizza tutti i componenti hardware e la superfice del disco. Altri test (di tipo software) non son in grado di analizzare il disco con questo livello di dettagli. Questo test ( e gli altri supportati ) può essere avviato manualmente nella pagina Informationi o automaticamente (tramite una pianificazione) nella maschera Operazioni (Solo con la versione Professionale).