Hard Disk Monitoring

I just bought a couple of Lenovo branded WD4001FYYG 4TB SAS drives which were advertised as brand new (old stock I assume). The model ID reported is IBM-ESXS WD4001FYYG-23S. They were supplied in sealed anti-static bags with Silica Desiccant pouches inside.

I just let HDSentinel loose on the first one and it reported Power on Time Estimated to be 136 Days 12 Hours and 50 Minutes. I've never seen an Estimated Power on Time before in HDSentinel, so thought I had better ask why this is only "Estimated"?

My other (non IBM/Lenovo) drives report Power on Time the same as would be shown by smartctl -l background on a Linux system (for a SAS drive)

Please could you explain what's going on here?

Thanks, David

> I just let HDSentinel loose on the first one and it reported Power on Time Estimated to be
> 136 Days 12 Hours and 50 Minutes. I've never seen an Estimated Power on Time before
> in HDSentinel, so thought I had better ask why this is only "Estimated"?

Different models may count the internal power on time differently. Some disk drives increase the internal counters
- once per second
- once (or twice) per minute
- once per hour
or even differently.

When Hard Disk Sentinel detects a new model (or a specific firmware which may work differently than expected) it verifies how often the internal counter changes to show the power on time based on the result. During this "analyse" period, it shows the word "estimated" because the reported power on time may be not correct until detection finished. This usually takes some minutes only: after that, Hard Disk Sentinel displays the power on time based on the calculation.

Most SAS drives count the power on time in minutes unit, so each value (you can verify on the S.M.A.R.T. page) may mean one minute of power on time.
But your drive may count/report the value differently.

It is always best if you
- make sure to use the latest possible Hard Disk Sentinel version. As described on the website, new devices always require newest version, as updated versions always have improved compatibility in general
- use Report menu -> Send test report to developer option, as these always help checking the status and the "raw" response of the drive. This helps to verify how a particular drive works and make changes/improvements if required.