HDD activity after being "safely removed"

[Guest]

Hello,
I've noticed that my external hard drive (a WD Elements Desktop) appears to be reading and/or writing data after being removed "safely". That is, I can still feel both spinning, as well as head activity by resting my hand on the enclosure.
After physically disconnecting the USB cable, the head activity stops and the drive spins down.
I am mostly surprised rather than concerned, as all data is perfectly fine. Can anyone explain why this happens? Why does the head still move?

PS: Neither the activity LED nor Process Monitor indicate any read/writes.

 

[buwish]

In the case of simply ejecting the drive from the computer, yes, the computer cannot read it anymore, i.e. is it still showing in my computer? But because it is still hooked into the USB port, the drive is still getting power, hence why you are feeling the activity.

 

[donpacific2k]

I just wanted to add that I have the same drive and noticed the same thing happening. (Vista 32bit). I've always waited to unplug until the head activity stopped and not had any problems. If I had to speculate, I'd guess the drive is just flushing the internal cache, but I don't know this for sure, and if so why it would wait to do that until the drive was "removed"

 

[craftapril]

i removed my hard drive safely and now 4 days later it is not showing on the computer anyway. it lights up and works, but it also has a lock that is lit up near the power button, if it is lock i don't see how to turn it off..