Hard Disk Sentinel 6.40.3

Hard Disk Sentinel is a Windows program for monitoring, testing and repairing storage devices. It reads the self-monitoring (S.M.A.R.T.) data that hard disks, SSDs, hybrid drives and NVMe drives report. It turns this data into a health rating, records temperature and attribute changes, and warns when a drive starts to deteriorate. It handles internal and external drives on SATA, NVMe, IDE, SCSI, SAS and USB connections, including drives in RAID arrays, pendrives and memory cards. A free command-line version for Linux and a bootable DOS version are also available.

How the health rating works

For each drive, Hard Disk Sentinel shows a health percentage, a performance percentage, power-on time and an estimated remaining lifetime. A colored text description explains the underlying problems, such as reallocated or pending sectors, spin-up failures or communication errors. It also suggests what to do next, including when to back up.

Health starts at 100%. Each critical attribute reduces it according to a weight. The program multiplies the remaining percentages together. Under the default method, two reallocated sectors give 98%, and five pending sectors on top of that give 95%. A stricter method intended for servers rates the same drive at 70%. A third method compares each attribute’s value with the manufacturer’s threshold instead of reading raw counts. SSDs without detected problems are rated from their own wear attributes, such as percentage used. You can set warning and alert levels globally, and per drive in the Professional edition. This suits SSDs whose health declines gradually through normal wear.

Tracking drive degradation

Hard Disk Sentinel records each drive’s daily minimum, average and maximum temperature and plots it alongside a graph of daily health. Per-device temperature limits prevent false alerts from NVMe drives that normally run warmer than hard disks.

Each drive also has a log. Whenever the raw value of a critical attribute changes, the program writes an entry with the time, the attribute and its old and new values. Such attributes include reallocated sectors, pending sectors or interface CRC errors. In the Professional edition, Device Specific Information reads the drive’s own error log and self-test history. On supported Seagate drives, it also reads the FARM log, which reveals whether the power-on hours have been reset.

Built-in drive self tests

Most drives contain built-in tests that Hard Disk Sentinel can start. The short test checks heads, servo, electronics and internal memory in a few minutes; the extended test adds a full surface scan that forces bad sectors to be reallocated. Neither changes stored data. A separate random seek test measures noise, seek time and temperature, and a run of eight hours or longer serves as a stress test. The Professional edition can schedule these tests.

Surface tests and sector repair

The surface test splits a drive into 10,000 blocks and colors each one by result. Green means normal, yellow marks blocks that needed retries, and red marks blocks that could not be read or written. Clicking a block shows the raw contents of that sector. Hard Disk Sentinel Standard offers a read test, which finds problems without changing data. It also offers a write test, which overwrites the surface so weak sectors are rechecked and bad ones replaced from the drive’s spare area.

Professional adds modes that repair or refresh without a full erase. Disk Repair reads the surface, makes the drive restore or reallocate weak sectors and then lists files stored on repaired sectors. A read-write-read refresh rewrites existing data in place, which also helps flash media whose cells lose charge over time. Reinitialization returns sectors to an empty state and can destroy data permanently. Quick Fix tests only likely trouble spots, such as sectors with logged errors, pending sectors, the partition table and file system structures. It runs up to five extra passes when sectors need repair. It does not replace a complete scan.

Responding to drive problems

Hard Disk Sentinel can react when health drops below a level, temperature rises, a new log entry appears or free space runs low. Responses include sounds, messages, e-mail, SMS through an e-mail gateway, a daily status report and a cancellable shutdown. In the Professional edition, a panic backup links disk problems to backup projects. A failing drive can therefore trigger copying its data to another disk, an FTP server or e-mail. The same projects can also run on a schedule. Professional can monitor NAS drives as well, by reading status reports the NAS is set up to produce.

Trial, Standard, Professional and Enterprise

The trial is the unregistered Professional program and serves mainly to confirm that drives are recognized. Standard and Professional licenses cover one computer each, and Enterprise adds a central console for monitoring and testing drives on remote computers.