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Re: [PLUG] stick drive that mounts as /dev/sda (or sdb....)
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> Date: Thu, 13 Aug 2009 09:40:27 -0700 (PDT)
> From: Edmond Rodriguez <erodrig_97@yahoo.com>
>
> Is there a reason why mounting a formatted usb stick drive with no
> partition table would be a bad practice?
I started to say, 'yes, you are writing to the "raw" disk' but then
looked into it a bit more and that seems to be valid sometimes.
> During a meeting about two months ago, I mentioned I had a 4GB usb
> stick drive that I could only mount to /dev/sda (or b or c etc..). I
> eventually learned I could mount it to /dev/sda (instead of sda1, or
> sda2 etc..)
I'm surprised no one else has mentioned this. /dev/sda refers to the
entire disk. /dev/sda1 refers to the first partition on that disk, sda2
to the second, and so on. I thought "entire" was also "raw" (i.e.,
without partition info), but I see in my /etc/fstab that:
/dev/hdc /media/cdrom0 udf,iso9660 user,noauto 0 0
/dev/fd0 /media/floppy0 auto rw,user,noauto 0 0
so it is valid at least sometimes. Maybe Linux treats /dev/sda and
/dev/sda1 as "the same" if there is only one partition?
The only other time I ever use /dev/sda is when I'm trying to nuke the
disk, like:
time shred -n3 -v -z /dev/sda
Wild-assed guess: maybe your USB drive isn't partitioned at all and you
are just writing to it raw? I would have guessed that that wouldn't
work at all, but maybe... Your "garbage" fdisk -l results might lend
some support for my theory. What do 'parted' or one of the other GUI
partition manglers make of it? If I were you I'd try to copy all the
data off the key and re-partition and re-format it from orbit--just to
be sure.
Here's what one of my keys looks like, stuck in my Mini9 running Jaunty:
$ sudo fdisk -l
[...]
Disk /dev/sdb: 1999 MB, 1999568384 bytes
255 heads, 63 sectors/track, 243 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x000eef8c
Device Boot Start End Blocks Id System
/dev/sdb1 * 1 243 1951866 b W95 FAT32
Can anyone else correct me or add more details?
Later,
JP
----------------------------|:::======|-------------------------------
JP Vossen, CISSP |:::======| http://bashcookbook.com/
My Account, My Opinions |=========| http://www.jpsdomain.org/
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