Re: Bios freaks

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Mikkel L. Ellertson wrote:
Tim wrote:
On Sun, 2007-08-19 at 18:52 -0600, Karl Larsen wrote:
I have heard a thousand words a week about LVM and it never made the
point that it moved /boot close to the near end of a hard drive.
I haven't heard about that happening.  It's always been my experience
that if you used the install routines to prep your drive, that it made
the /boot partition the first one.  I don't know if that's coincedental,
but it would be a good thing for it to deliberately do.  Other
partitions get shuffled about, though.  I don't know the reasoning
behind it (if there is any).

I don't think Karl understood what people were trying to tell him.
The problem is not LVM moving /boot close to the end of a hard
drive, but that when you have /boot as part of the / partition,
instead of giving its own partition, the files in /boot may end up
towards the end of the drive.

e.g. If you had created /boot/, /home/, /tmp/, /usr/, /var/, in that
order, you might find that at the end of your manual intervention, it
actually created the partitions in another order, albeit with /boot/
being the first partition.

Of course, thanks to how drives fake their number of heads and
cylinders, to accomodate how BIOSs (and IDE?) are still terribly poor at
handling large drives, there's still no guarentee that all of the first
partition is going to be where the BIOS can access it.

The drives internal remapping should have no affect on what the BIOS
can access. The BIOS just tells the drive I want this track, head,
sector, and it could care less where it really is on the drive. If
the partition is the first x blocks on the drive, the BIOS can
access it, regardless of the physical location on the drive, as long
as the logical h,t,s is in the range the BIOS can handle.

Mikkel
You have not been following the other thread bash. I checked just now and my /boot is at /dev/sdb6 and it works fine. Here is fdisk -l


Disk /dev/sdb: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

  Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *           1        1217     9775521   83  Linux
/dev/sdb2            1218        1945     5847660   83  Linux
/dev/sdb3            1946        1961      128520   82  Linux swap / Solaris
/dev/sdb4            1962       18534   133122622+   5  Extended
/dev/sdb5            1962        7060    40957686   83  Linux
/dev/sdb6            7061       12159    40957686   83  Linux
/dev/sdb7           12160       18534    51207156   83  Linux
[root@k5di ~]#

Notice that sdb6 starts at 7061 cylinders! And the grub boot works fine to a setup on the first hard drive (hd0) :-)

The 1994 BIOS is reading the grub message and going to another hard drive finds the /boot at 7061 cylinder. 8-)

Puts a crimp in your theory.



--

	Karl F. Larsen, AKA K5DI
	Linux User
	#450462   http://counter.li.org.


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