Grub Manual

[John Summerfield]

Jacques B. wrote:
>> In a running system, it's the base of the mounted filesystem.
>>
>> In a partition, it's the base of the partition. For the root filesystem,
>> and only for the root filesystem, they're the same.
>>
>> grub, the boot loader, does not deal in mounted filesystems, it only
>> looks at a single filesystem, typically but not necessarily, in a partition.
>>
>> How about you print this before commenting further?
>> http://www.gnu.org/software/grub/manual/grub.ps.gz
>>
>> One of the better things about GNU's documentation is that the same
>> files that create the info files can also create postscript and PDF files.
>>
>>
>> Cheers
>> John
>>
> 
> The beauty of a debate.  Makes people think.  I did some digging and
> found the following:
> http://www.redhat.com/docs/manuals/linux/RHL-9-Manual/ref-guide/s1-grub-terminology.html
> Where you will find a section called "GRUB's Root File System" which says:
> ------------------------------------------------------------------------------------------------------------------------------
> Some users are confused by the use of the term "root file system" with
> GRUB. It is important to remember that GRUB's root file system has
> nothing to do with the Linux root file system.
> 
> The GRUB root file system is the root partition for a particular
> device. GRUB uses this information to mount the device and load files
> from it.
> 
> With Red Hat Linux, once GRUB has loaded its root partition (which
> equates to the /boot partition and contains the Linux kernel), the
> kernel command can be executed with the location of the kernel file as
> an option. Once the Linux kernel boots, it sets the root file system
> Linux users are familiar with. The original GRUB root file system and
> its mounts are forgotten; they only existed to boot the kernel filI
> 
> Refer to the root and kernel commands in Section 2.6 GRUB Commands for
> more information.
> -------------------------------------------------------------------------------------------------------------------------
> 
> Based on that I have to conclude that what Karl stated isn't
> necessarily incorrect (my apologies).  It did lack some clarification
> differentiating between grub's root file system vs the OS root file
> system.  However Karl was not correct through knowledge of this, but
> rather by accident.  He was of the opinion that anything that was on
> its own partition had a root and could be properly referred to using
> that term.
> 
> Ultimately it goes back to refraining from posting authoritative
> instructions unless one is an authority on the subject.  Of course the

Probably whenever anyone posts an authoritative statement, they believe 
not only that they're right but that they're suitably qualified.

When I'm uncertain, I try to qualify my statements ("I think," "Maybe," 
and so on), but I still make a fool of myself sometimes.


> same could be argued for those of us posting a rebuttal.  In this case
> Karl's understanding of how to use the term root was erroneous.
> Others were using it properly however were unaware of grub's own use
> of the term (myself included).

Context is important. The only thing special about / is that it's the 
base of what one can see at the time.

If I have F7 on /dev/sda1 and Etch (Debian) on /dev/sdb1, it is 
perfectly possible for me to mount /dev/sdb1 at /var/local/debian when 
running Fedora, and to mount /dev/sda1 at /var/local/Fedora when running 
  Etch.

Each filesystem has its own root. What the kernel sees as / is just a 
special case.

It can get more complicated when one starts using virtual machines, 
chroot and so on.


-- 

Cheers
John

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1aaaaaaa at coco.merseine.nu  Z1aaaaaaa at coco.merseine.nu

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