Drive Alert is a hard drive warning system that will warn the user of impending hard drive failures while there is still time to take action, such as backing up data to a replacement device. Drive Alert will display a green hard drive icon in the finder menu when all monitored drives has been verified as good and will turn red if it detects that a failure is going to occur.
Think of Drive Alert as your own engine light that will turn red and alert you with a message when it suspects the drive is failing from a hardware defect.
You can choose from different intervals to check hard drives and also select what hard drives to monitor, Drive Alert will only support internal drives that are ATA, SATA or eSATA at the moment.
Drive Alert uses S.M.A.R.T. (Self-Monitoring, Analysis and Reporting Technology) that is implemented in all modern Macs.