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Re: Question about umount and sync

From	Joe Beanfish <joebeanfish@nospam.duh>
Newsgroups	comp.os.linux.development.apps
Subject	Re: Question about umount and sync
Date	2012-06-29 15:47 -0400
Organization	A noiseless patient Spider
Message-ID	<jsl0od$tlb$1@dont-email.me> (permalink)
References	<jskm1r$54e$1@news.albasani.net>

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On 06/29/2012 12:44 PM, Jan Panteltje wrote:
> Question about umount and sync
>
> In the long ago past you could type 'sync' 3 times to make sure a disk
> was umounted..
> Then later I used umount, and it returned when all data was written.
>
> But I notice on my new 16GB USB sticks that the busy light just keeps flashing
> for up to a minute after umount and sync have long returned.
> So what is a reliable way to umount these things from for exmaple a script,
> and be sure before allowing the user to unplug such an USB stick?
>

umount has always been and still is the way to unmount. It will call
sync then detach the filesystem from the OS in a safe way so there's
no lost data. Sync just flushes the buffers. No amount of syncing does
or ever did properly detach a filesystem from the OS. Pure luck kept
you out of trouble using that technique.

The ongoing activity is probably the USB bus probing etc. Don't worry
about that. Umount is definitive.

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Thread

Question about umount and sync Jan Panteltje <pNaonStpealmtje@yahoo.com> - 2012-06-29 16:44 +0000
  Re: Question about umount and sync Joe Beanfish <joebeanfish@nospam.duh> - 2012-06-29 15:47 -0400
    Re: Question about umount and sync Jan Panteltje <pNaonStpealmtje@yahoo.com> - 2012-06-30 06:20 +0000
    Re: Question about umount and sync Richard Kettlewell <rjk@greenend.org.uk> - 2012-06-30 13:16 +0100
      Re: Question about umount and sync Joe Beanfish <joebeanfish@nospam.duh> - 2012-07-02 10:07 -0400
    Re: Question about umount and sync ameliusje@gmail.com - 2014-08-18 12:58 -0700
      Re: Question about umount and sync Joe Beanfish <joebeanfish@nospam.duh> - 2014-08-19 13:29 +0000
        Re: Question about umount and sync Jan Panteltje <pNaonStpealmtje@yahoo.com> - 2014-08-19 14:09 +0000
          Re: Question about umount and sync Joe Beanfish <joebeanfish@nospam.duh> - 2014-08-21 13:22 +0000
            Re: Question about umount and sync Jan Panteltje <pNaonStpealmtje@yahoo.com> - 2014-08-21 14:15 +0000

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