On Thu, Jan 21, 2010 at 11:34:48PM -0800, Johan Beisser wrote:
> On Thu, Jan 21, 2010 at 10:43 PM, Song Li <lis...@stanford.edu> wrote:
> > On Fri, Jan 22, 2010 at 6:44 AM, Bret S. Lambert <bret.lamb...@gmail.com>
> > wrote:
> >> On Fri, Jan 22, 2010 at 05:42:25AM +0100, Song Li wrote:
>
> > "fdisk sd0" is not a problem to me now either after I've seen Aaron's
> > comments on fdisk. The problem on mount still exists though:
> >
> > What seems a little counter intuitive to me is: I would see sd0 as a
> > shortcut of /dev/sd0 for fdisk, but "fdisk /dev/sd0" does not work.
>
> sd0 is not the whole disk. It indicates "scsi disk device 0." There
> are other partitions on the whole device ("c"), that get referenced.
>
> As stated in disklabel(5)'s CAVEATS, by convention, scsi disk device
> 0, partition "c" would be the whole drive by convention.
>
>
> > In addition, the fact that we need "mount /dev/sd0i /mnt/usb" and the
> > slice letter 'i' seems weird to me. I can now see the possible
> > rationale behind: OpenBSD assigns slice letters for *all* devices
> > together in sequence, while other OS may just start it over for a
> > different device. OpenBSD may have a reason for this design but that's
> > what confused me, esp., after the change of device name from ad to wd,
> > and the alias of /dev/rwd0c for wd0, etc.
>
> You could makefs on /dev/sd0c instead. Nothing really forces you to
> create other slices (or partitions) on the device.
Bad advice. disklabel does not record some redundant information for
the c partitiion. Which may bite you in case of a superblock
corruption due to power loss, for example. In that case, fsck_ffs is
not able to reconstruct some vital data needed to do its work. Never
use the c partition for a file system.
-Otto
