Turn off drive after "Safely Remove"? [duplicate]

In Windows XP, the "Safely Remove" feature would completely turn off power to the associated USB port. (If the device is self-powered, its behavior depends on the device itself, in response to the comments above.)

In Windows Vista and above, this feature has been intentionally removed:

Microsoft Support: The Safely Remove Hardware feature does not stop power from being provided to a USB device in Windows Vista

Cause: The Safely Remove Hardware feature does not stop power from being provided to a USB device in Windows Vista. By design, the port to which the device is attached is not suspended in Windows Vista when the device is soft removed.

This is how you can enable it per device VID&PID or globally:

Microsoft Support: USB Port Remains Active for Disabled or Safely Removed USB Device

Resolution: To work around this problem, a registry value can be set to cause Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2 to revert to the Windows XP and Windows Server 2003 behavior of disabling the USB hub port to which a Soft Removed USB device is attached. This workaround can be applied on a per-device basis (for all instances of a specific device (Vendor ID, Product ID, and Revision), or globally (for all enumerated USB devices).

[...]

Global Setting

To apply the workaround globally for all enumerated USB devices, add a REG_DWORD value named DisableOnSoftRemove that has a value of 1 to the following registry subkey: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\usbhub\HubG

Use the following command to add the global setting value:

reg add HKLM\SYSTEM\CurrentControlSet\Services\usbhub\HubG /v DisableOnSoftRemove /t REG_DWORD /d 1 /f

I've tested this on Firewire and eSATA drives (well, the same drive but using those 2 different connectors), and the behavior on my Seagate drive is to simply unmount the drive, causing the external drive to behave as if the data cable had been disconnected—the HDD's light begins to dim and then turns off.

However, the drive itself doesn't actually turn off, even though it may appear to be (no spinning, no sound, no lights). This is so that the standard re-mounting procedure in Windows (disconnecting and reconnecting the Firewire/eSATA cable) will allow the drive to be re-mounted.

I believe the procedure on Macs is slightly different, and you can just re-mount it in software. (You can probably do the same thing in Windows 7 by disabling/re-enabling the USB/FireWire/SATA device in Device Manager, but it's kind of a pain.) But this too would require that the drive doesn't get shut off when you eject the disk.

As a side note, many external HDDs, such as mine, do not have a power switch. The only way to actually turn off its power is to disconnect the power cable. And the way to turn it on is to simply plug the power cable in. Otherwise, the HDD just goes into standby or sleep mode.