Question HDD 2.5" internal construction and shock protection ?

[USAFRet]

The Windows eject (safely removing hardware) option cuts off the electrical current through USB3.0. Is this why the 2.5" HDD + USB3.0 case is parked?

Generally, it looks like ANY cutoff of power engages the parking function. Not just safely EJECT in Windows.
Reading the above quote, some drives are doing this with a mechanical spring. Others, use the momentum of the spinning drive.

 

[cloudff7ps1]

The Windows eject (safely removing hardware) option cuts off the electrical current through USB3.0?

 

[USAFRet]

The Windows eject (safely removing hardware) option cuts off the electrical current through USB3.0?

Just to be safe, always Eject.

Whether it cuts off the power or not, that would presumably send it the park command.

The exact specifics of any singular drive are probably irrelevant.
Anything made this century has some auto parking thing going on. Specific technologies of how vary, but they all do it.
(and no, I do not know what your particular drives do. Nor am I going to attempt to look it up.)

 

[USAFRet]

Anecdotally:

500GB Seagate "Laptop Thin HDD"
Manufactured 18 Oct 2016.

This is a sacrificial drive and data. Do not attempt this at home.

Lived in a corporate laptop until mid 2022.
Then kicked around in various desk drawers until Oct 2024.
No special care taken to treat it gently.

Plugged into a toaster style dock, works perfectly.

Test 1:
Full Format, copy 41GB data to it. Approx 1,500 files of various types.

Test 2:
Toss into the air approx 3 m/10 ft, allowing it to fall onto a grass surface.
Plug it into the dock, Read/Write works perfectly.

Test 3:
Carry to 20m/65.6ft via quadrotor.
Drop, and fall to same grassy surface.
Plug into the same dock, it does not appear to have survived.

 

[cloudff7ps1]

What command is sent from Windows to the 2.5" HDD + USB3.0 case you are referring to?

Does this command, regardless of the case, remain connected to the PC via the USB3.0 cable?

 

[USAFRet]

What command is sent from Windows to the 2.5" HDD + USB3.0 case you are referring to?

Does this command, regardless of the case, remain connected to the PC via the USB3.0 cable?

Did you read that linked article?
(or any of the dozens of other articles related to head parking)

There are multiple different ways a drive will auto park, or sense if/when they need to.
But, it is safe to say, ALL of them in current use do it.