[wellylug] RE: Copying from USB stick in Redhat server

[Daniel Pittman]

Peter Dawson <peter_dawson at eagle.co.nz> writes:
>> Date: Sun, 25 Mar 2007 22:48:44 +1200
>> From: Jethro Carr
>> Subject: Re: [wellylug] Copying from USB stick in Redhat server
>
>> On Sat, 2007-03-24 at 11:21 +1200, John Durham wrote:
>> > > umount /mnt/usbstick
>> > > 
>> > > Sometimes with SCSI devices you need to use eject as well
>> > > 
>> > > eject /dev/sda
>> > > 
> 8><=== snip...
>
>> I've never heard of needing to use eject on a USB stick before - you
>> did make sure that the > umount command had finished didn't you? It
>> will return you to a prompt once complete.
>> 
>> Sometimes it takes a few seconds to complete, as it has to write the
>> cache to the disk before it can umount the filesystem - if you were
>> to pull it out whilst this was happening, you'd get the errors.
>
> I recently saw a comment somewhere that mentioned that some USB
> devices seem to be programmed to expect a particular command sequence
> to disconnect properly, 

Yes -- a SCSI disconnect command.  Normally these are devices like the
iPod that display a specific message to show they are busy, because
without that the end user can't actually tell when the process has
completed.

Your typical flash USB stick doesn't require that sequence -- though the
OP may have an atypical model. :)

[...]

> Personally, I have taken to using eject rather than umount when an
> intelligent device is being disconnected. It doesn't appear to have
> caused any problems yet... YMMV

Well, for a normal device it calls umount for you, so the system can't
tell the difference. 

Regards,
        Daniel
-- 
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