HDDScan is a freeware utility for hard drive diagnostics (RAID arrays and Flash USB drives are also supported). The program can test storage device for errors (Bad-blocks and bad sectors), show S.M.A.R.T. attributes and change some HDD parameters such as AAM, APM, etc.
HDDScan can be useful for performing the regular "fitness test" for your drive and predicting its degradation, so you will be able to prevent data loss and backup your files before you will have to contact the data recovery service.
Additionally, the software can be used as the hard disk temperature monitor and reading/writing, and a benchmark performance graph is displayed for every test.