From H.D.S. Hungary:

Hard Disk Sentinel monitors hard disk status, health and performance including temperature and S.M.A.R.T. (Self-Monitoring, Analysis and Reporting Technology, built in most hard disks today) values for each hard disks. Also it measures the hard disk transfer speed in real time which can be used as a benchmark or to detect possible hard disk failures, performance degradations. Hard Disk Sentinel can be used to prevent serious damage or data loss. It warns the user before a problem may occur and this gives opportunity to backup important and valuable data.