[TriLUG] / is /dev/root and not /dev/sda?

[Cristóbal Palmer]

On Tue, Jun 12, 2012 at 6:06 PM, Joseph Mack NA3T <jmack at wm7d.net> wrote:
>
> o if you don't understand it, you shouldn't be on this group

What group? TriLUG? This mailing list? We don't have some linux
knowledge test to join, and implying so is not friendly to those who
are starting out. We welcome anyone and everyone who wants to discuss
and learn about linux in a friendly manner. Perhaps this was a
self-deprecating joke. If that's the case and I missed the cue, please
forgive me.

> o I don't get this output on my machine.

What output?

> o there are many people mystified by why / is now /dev/root

Haha. Why this is funny will soon be clear.

> o you can fix it with the attached patch (which I didn't see, perhaps
> because I was a guest on that forum)

Note that this mailing list strips attachments, too. If people have
code to share, use a pastebin of some sort and include a link.

I have a vague memory of referencing /dev/root in a dd operation back
in roughly 2004, but the earliest easily found and easily dated
reference I have is a dunno from Tribot:

./2007/freenode/tribot.12-17.log:02:24 <Tribot> Dunno #13: "/dev/root:
No space left on device" (added by Nivex at 12:08 AM, November 14,
2006)

So we know it was around then. We also know that it's not just Linux,
it's IRIX, too:

http://menehune.opt.wfu.edu/Kokua/SGI/007-2825-012/sgi_html/ch05.html

Some slackware users wondered about it back in 2008:

http://www.linuxquestions.org/questions/slackware-14/slackware-current-dev-root-688189/

Google helped me find it in Linux back in 2003:

https://www.kernel.org/pub/linux/kernel/people/gregkh/misc/2.5/devfs-cleanup-2.5.40.patch

Ditto, this time for the 2.4 kernel:

http://www.kernel.org/pub/linux//kernel/people/marcelo/linux-2.4/Documentation/filesystems/devfs/ChangeLog

And that last one provides a real "Aha!"

-----8< snip 8<-----
- Created /dev/root symlink
  Thanks to Roderich Schupp <rsch at ExperTeam.de>
  with further modifications by me
-----8< snip 8<-----

and more searching based on that puts it at 1998:
http://lkml.indiana.edu/hypermail/linux/kernel/9810.0/0515.html

I'll reserve research on the history of devfs and the rationale for
the /dev/root alias for another day. For now, I'll ask what your
/etc/mtab shows, because I'm guessing that shows the right pairing of
/ and the underlying device you want.

Cheers,
-- 
Cristóbal Palmer
cmpalmer.org