On Thu 19 Jul 2007, at 15:43, Momchil Ivanov wrote:
On Thursday 19 July 2007 09:17:48 [LoN]Kamikaze wrote:
Norberto Meijome wrote:
On Wed, 18 Jul 2007 17:41:04 +0200 (CEST)
Oliver Fromme <[EMAIL PROTECTED]> wrote:
another work-around
is to use the auto mounter daemon (amd(8)). It umounts
file systems automatically that are not in use.
Another nice feature of amd(8) is that you don't have
to mount the file system either -- Simply plug the USB
stick in, then access it, and amd(8) will automatically
mount it for you.
Now, something I dont understand - amd runs
at user level, and it mounts filesystems, and nothing dies when the
filesystems go away (other than the obvious cases for the
applications
trying to write to the FS in question). Doesn't amd , at some
point ,
have to tell the kernel 'please mount this filesystem' here or
there?
Isn't the kernel STILL involved in all this? and why doesnt the
kernel
panic when the FS goes away?
The trick is that amd unmounts the device after a couple of
seconds, so
when someone accidentally removes a usb drive, it doesn't really
matter.
Amd will simply fail to mount it on the next access. If you remove
the
device during or shortly after accessing it, it still will panic the
system.
What is then the reason for the kernel not being able to unmount a
filesystem
whose provider is no longer present? What in the process of
unmounting denies
unmounting a filesystem whose provider is no longer available? Why
can the
kernel not just inform all programs that files have to be closed
and are
unaccessible any more, then consider the fs as unmounted and remove
any bits
of it left in the VM. Why can kernel not just ignore interruped/
pending
writes to that fs, drop the data, return an error to the program that
initiated the write and just go on.
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Hi,
How Mac OS X handle this? Method, tricks, code, etc...
Does Linux reboot when this happen?
The kernel is different between OS X, Linux and FBSD.
Why FBSD handle this by reboot? Does reboot clean up everything?
BTW,
I hardly ever put a USB Disk on our FBSD Servers,
but never had problem disconnect USB/Firewire Disk on my Powerbook.
Julius
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