Does/Should removable, internal hard drive spin down when ejected?

Hi there.

Simple physics 101 -- Momentum (mass X velocity) - in this case angular momentum. You can't stop say a device weighing a few grams rotating at 7200 RPM instantly especially is as should be the bearings have minimal friction so it will spin down for a little while.

The important thing is not to remove the HDD's until the computer signals safe to remove hardware -- at that point data transfer has ceased and the HDD is just spinning down - doesn't matter if it's in or out of the computer at that point.

Might be better to leave in the computer until it's stopped though as you might drop it while it's still spinning -- won't do the HDD any good !!!.

Note on VM's when you detach a drive the same is true - also if the HDD has a LED wait until the LED is steady or even off before removing the device.

Cheers
jimbo

GracieAllen said:

My question is WHAT happens between when I do a "safely remove" and when I actually grab the drive and pull it off the plug. Is it, or is it NOT still spinning.

1. operating system dismounts all filesystems affected by drive removal
2. disk controller sends ATA commands Flush Cache and Standby Immediate to drive affected

Not all devices support required ATA command Standby Immediate (which does heads park & spin off), esp. SATA controllers in RAID mode. Further reading:
http://www.t13.org/documents/Uploade...nd_Set_-_4.pdf
http://download.microsoft.com/downlo..._detection.doc
http://dlcdnet.asus.com/pub/ASUS/mb/...UXE_UG_WEB.pdf

remove power first (big drive) or self powered drive will spin down when unplugged, I do think the shock of being pulled off like that wears them down over time, might hold it steady until its quiet, me personally, I keep my PC on all the time and have 8 internal, 6 spinners, and 2 external in good rocketfish enclosures, not the flimsy mybooks etc. I let my drive continually spin, I have found this to be the best option unless the computer is never used or moved a lot. (2 drives failed on me in my life, both Seagate, many mybook enclosures failed with good drives that could be reused) and a box full of perfectly good drives all the way back to 20gb ide cabled drives.

while my friend toted a pc I gave him with him to deer camp and other places as a movie server, he killed to 500gb drives easily and quick and these were drives that parked when he shut the computer down