Re: usb flash drive removal (Re: Desktop NetBSD needs your help)

[David Young <dyoung%pobox.com@localhost>]

On Wed, Feb 11, 2009 at 11:30:26AM -0700, Sverre Froyen wrote:
> On Wednesday 11 February 2009, Stathis Kamperis wrote:
> > 2009/2/11 Jared D. McNeill <jmcneill%invisible.ca@localhost>:
> ...
> > >
> > > Maybe we should add it to the Google Summer of Code project list.
> > >
> > > Jared
> >
> > It is already there:
> > http://www.netbsd.org/contrib/soc-projects.html#disk-removal
> 
> I wonder if there is a simpler (80%) solution -- and forgive me if this has 
> already been suggested or if it is is impractical to implement (I am only 
> marginally familiar with the file system code).
> 
> I notice the USB devices usually (always?) contain a light that flashes while 
> the device is being accessed -- sort of like floppy drives in the old days.  
> This serves as a strong reminder to the user that she should not unplug the 
> device.  The issue therefore is what to do if the user unplugs an idle device.

Relying on an access LED to discourage the user from disconnecting it is
fraught with problems: not every drive has an access light.  You have to
start flashing an access light well ahead of the time of access, because
the system will always win a race to start an access before the user can
remove the device.  Also, an access LED does not discourage accidental
disconnection.

Dave

-- 
David Young             OJC Technologies
dyoung%ojctech.com@localhost      Urbana, IL * (217) 278-3933