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Yes, I know somewhat about the possibility of data corruption if there was data that hadn't been all written to it.
But I just saw this:
Note:If u remove HDD(not USB sticks) without safely removing it,its not healthy and will affect life.
So, if nothing is actually writing to it, could there actually be any harm caused by not safely removing or unmounting it before disconnecting it?
Nathaniel
Posted 2010-04-02T01:26:52.120
Reputation: 3 966
5
No! Cached data may not be written yet. Regardless of your OS, you have to inform it that you're yanking.
OSes do write-caching (and read-caching) to make drive access faster.
Dan Rosenstark
Posted 2010-04-02T01:26:52.120
Reputation: 5 718
What if I never actually wrote any files to the disk, I only read files? – heavyd – 2010-04-02T01:45:05.643
3Some file systems include last accessed times in the file metadata so reading a file DOES write to the disk. – Chris Nava – 2010-04-02T02:36:30.987
What if I ask it to safely unmount and it says something is still accessing it when I can't fine anything that is? Is there a way to force an unmount? – Nathaniel – 2010-10-08T00:15:22.997
1@Nathaniel no. But in many cases you can take your chances and nothing bad will happen ;) – Dan Rosenstark – 2010-10-08T22:44:59.337
@Yar, because of journalling filesystems this rarely happens. FAT frequently had to be chkdsk'ed. – Thorbjørn Ravn Andersen – 2010-10-23T13:35:36.273
1@Thorbjørn Ravn Andersen makes sense and matches my empirical observations (i.e., I just unplug drives randomly all the time, with no ill consequences :) ) – Dan Rosenstark – 2010-10-23T22:29:06.003
1@Nathaniel, I might mention that one app that accesses stuff when you least expect it is the Finder itself. So learning to kill tasks on the OS is essential, but you probably know how to do that already. – Dan Rosenstark – 2010-10-23T22:30:49.140
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When you run the safe removal process, commands are sent to the disk to cause it to spin down and park the heads: in contrast if you disconnect the power suddenly then an emergency unload is done, which uses remaining power to move the heads away from the surface. That movement is violent and so disks are rated for a far fewer number of emergency unloads than the standard parking of the heads. So by pulling the power you may indeed be causing physical damage to the actuator mechanism.
BCran
Posted 2010-04-02T01:26:52.120
Reputation: 196
That... is a good observation. – Nathaniel – 2010-11-23T00:52:52.340
I have an external hard disk which is never can be safely removed (it always says "Cannot remove, still in usage" or something like that). Would you be so kind to give a tip to make it safely removable? – deathlock – 2013-06-25T14:36:49.710
good question...+1 – studiohack – 2010-04-02T02:31:05.787