fedorafedora-17linuxsafely-remove-hardware
In Fedora 17, when I want to plug my USB hard disk out, I can only unmount it. But the problem is that the hard drive won't be powered off so that I can plug it out.
In some other distros like Ubuntu there is a Safely Remove option which powers the hard drive off.
How can I fix that?
No, but it does not mean it is a death sentence if you do.
You can not guarantee that all the writes have been flushed out, but after several minutes of sitting it is likely that the data is flushed out. However, you may have some issues with some filesystem maintenance things that don't happen until you unmount if you are in "Performance mode" (see the next paragraph)
However there is another option (and it is likely already set for 99% of all removable media). If right click on the device and go to properties. Then from there go to the hardware tab and find your device.
Click Properties, then click on the Change Settings button on the new page. Go to the Policies tab.
If you device is set to "Quick Removal" you can remove your device without going though "Safely Remove Hardware" without worrying about data loss.
If you do not have a Policies tab you likely skipped the Change Settings step.
/dev/sdb is the whole device. /dev/sdb1 is one partition on that device.
While you could use a disk without partitioning it, that's rather unusual (outside of RAID setups, but then you make the filesystems on the raid device nodes, not the physical device nodes).
It doesn't really make sense to try to detach (physically remove) a single partition – you want to remove the whole device (that can contain multiple partitions), not just one partition of that device.
Unmounting a partition will synchronize the filesystem, so calling sync before unmount is not necessary.
Calling udisks --detach on the device checks that you have no filesystems mounted on that device (you should make sure that that call does indeed succeed), and will perform an "orderly shutdown", which is always preferable to a "pull the plug" approach, regardless of whether that particular device does anything special.
Best Answer
After a lot of web surfing I came across the solution suggested by someone in askubuntu.com. Thank you everybody. I just needed to install udisks package! To power off my hard disk I have to enter the following command in terminal after unmounting all of its partitions: