A USB drive is designed to be "hot-plugged" and unplugged again
later. But there are some rules.
1) Windows used file locks. Say you're in Microsoft Word, and you
open "readme.doc" on the Mybook and start making changes. If you
pulled out the hard drive right this instant, your work could be lost,
or even the file could be damaged. The software has the
expectation that the drive will be there while the software
is doing its work.
2) At the bottom right of the screen, when you plug in your Mybook,
you'll see a "Safely Remove" icon. If you use that icon, it provides a
way to tell Windows, that you're about to disconnect the drive.
Windows can issue a command to the drive, to flush any software
data cache in Windows itself, and flush the hardware cache on
the hard drive controller. Caches are "lazy" and not in a rush
to write all the data out to the hard drive platter. If you
use the "Safely Remove" icon, that starts the process of
alerting everything associated with the drive, that the drive
is going away. The cleanup process ensures any outstanding
data is transferred safely to the platter of the disk.
3) If there are any files still open, or even a program running
which is "looking" in the directory on that disk, the
"Safely Remove" may report the disk is "busy". It is your
job, as the user, to close that "readme.doc" file you
were looking at. If "Safely Remove" still refuses to let
you unplug the disk, next you'd quit Microsoft Word, to make
it stop looking at the disk. As a user, you have to use a lot
of intuition (guesses), as to what is holding up the disk.
No OS really does a good job of this, and when it comes time
to dismount a volume, they never come out and say "hey stupid,
close the readme.doc file". Sometimes, you can find a utility
which can report open files, but again, they may not be the
easiest tools to use, and may deluge you with stuff you don't
want to know.
In summary, yes, you can unplug your Mybook in mid-session. Close
all open files, stop any programs which may be still looking at
the disk, and then use the "Safely Remove" icon. You should
receive feedback when the cleanup operation has completed
successfully, and then you can finally unplug the disk.
You don't have to quit all programs. There may be innocent
programs, which aren't using the Mybook at all. They can
continue to run. But if the "Safely Remove" gives you
a hard time, try to remember which tool you were using,
which may happen to have used the Mybook. Quitting that
program, may be enough to allow the cleanup operation
to finish.
If you get in a situation where you've closed all open
files, quit all programs, and the "Safely Remove" still
won't finish the job, then doing a shutdown would get
the job done. There could be things going on in the
background that you don't know about, like say your
AV program is messing around. Or some program is
"stuck" or the file system is marked busy when
it really isn't busy. A shutdown would allow you
to unplug the disk.
That isn't all possible rules or scenarios, but that
should give you some idea how it works. For example,
I didn't address what happens when the computer is
in standby or hibernate, with respect to the Mybook.
If you "Safely Remove" before you standby or hibernate,
that should be pretty safe. You'll have to use your
imagination for the other cases
Paul
