On Mon, 31 Mar 2008, vze284qe(a)verizon.net wrote:
> On Sun, 30 Mar 2008 21:25:28 -0400
> Mike Frysinger <vapier(a)gentoo.org> wrote:
>
> > On Sunday 30 March 2008, Chuck Noyes wrote:
> > > I had mounted an external usb drive /dev/sdb2 onto /media/sdb2 and
> > > was coping several mega-bytes of files to it when I got some I/O
> > > errors. Then I noticed that all of my /dev/sdb* files were missing
> > > from /dev.
> > >
> > > When I do an ls -al /dev, all the files are there except the sdb
> > > files.
> > >
> > > How can I get these back? I'm running Ubuntu 'gutsy'
> > > 2.6.20-16-generic.
> >
> > the device nodes only exist as the kernel thinks the device exists.
> > if you got I/O errors and then the device nodes disappeared, the
> > kernel probably detached the device. so even if you made the device
> > nodes by hand, it wouldnt matter as the kernel still wouldnt think
> > the device was attached. review your `dmesg` and if need be,
> > unplug/plug in the USB device. -mike
>
> Well....this is really strange!
>
> I booted up another kernel a 2.6.18, and I noticed that the /dev/sdb*
> files were still missing! All of the other /dev files were there.
>
> So I shut down the computer - power off, unplug, remove battery (it's a
> laptop) and waited a minute. I reinstalled the battery, plugged it in
> and booted up the usual kernel, et voila...the /dev/sdb* files
> reappeared!! All looks good! Even Linux has some strangeness I guess.
>
> I don't know what caused this in the first place...transient lightning
> bolts? spurrious darktrons?
A few thoughts...
Is the external USB drive self-powered? Did you power-cycle it at
any point? The device itself might have gotten wedged.
It might have shown up as /dev/sda* on some of those interim reboots,
depending on whether there were any other usb storage devices present.
"lsusb", and the tail command Eric suggested, are your friends.
What is sda currently?
[ these work on 2.6.23, not sure about earlier kernels ]
$ cat /sys/block/sda/device/model
$ cat /sys/block/sdb/device/model
Anyway, glad to hear it at least works again.
-Jamie
