SIGuardian is the only tool what allows you full control over the health of your HDDs, and prevents data loss because of failures. Using S.M.A.R.T. technology included in all modern HDDs SIGuardian predicts the end date of HDD lifetime, so you can make backup copies of all your data before it's to late. S.M.A.R.T. [Self-Monitoring, Analysis and Reporting Technology] - an "industry term of art" that describes the technology used to monitor and predict device performance. You can read more about it on Quantum, Maxtor or Seagate site.