Triple boot:XP,ubuntu&FC5 grub failed

Mike McCarty Mike.McCarty at sbcglobal.net
Wed Sep 6 19:36:12 UTC 2006


Tod Merley wrote:
> On 9/6/06, Mike McCarty <Mike.McCarty at sbcglobal.net> wrote:
> 
>> Tod Merley wrote:
>> > Hi Gayal Rupasinghe and Jim Cornette!
>> >
>> > Gayle, Jim has it pretty much right I think.
>> >
>> > The chainload of Ubuntu (sort of a "stop looking here and start fresh
>> > right there!) should see a Fresh MBR (this is were I have a bit of a
>> > question since I can only see an MBR as being generated for the first
>> > sector of the disk) immediately followed (and referenced in the MBR)
>> > by a file within your current /boot/grub called "reiserfs_stage1_5".
>>
>> [snip]
>>
>> Erm...
>>
>> There is exactly one (1) MBR per physical fixed disc. Each non-extended
>> partition has a BR on it (sometimes called the geometry). GRUB
>> can run either from the MBR or from a BR. Extended partitions are
>> another story altogether.
>>
>> Mike
>> -- 
>> p="p=%c%s%c;main(){printf(p,34,p,34);}";main(){printf(p,34,p,34);}
>> This message made from 100% recycled bits.
>> You have found the bank of Larn.
>> I can explain it for you, but I can't understand it for you.
>> I speak only for myself, and I am unanimous in that!
>>
>> -- 
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>>
> 
> Hi Mike McCarty!
> 
> So when you use a GRUB prompt or grub-install you can form a Boot
> Record on any of the four Primary Partitions (the very first one being
> the Master Boot Record of course)?

Not quite. A BR is a part of a partition. The MBR is outside of any
partition, and contains the definitions (the Partition Table, or PT)
of the partitions as a part of it.

Using the classic layout, the PT has room for up
to 4 entries, at most one of which may be an extended partition.
Primary Partitions each have a BR which contains, as a part of it,
the BIOS Parameter Block (BPB) or the so-called geometry. An extended
partition may contain logical (as opposed to physical) volumes.
(Do not confuse these terms with the Red Hat "Logical Volumes".)
There is no arbitrary limit on the number of logical volumes may
be contained in an extended partition. Each logical volume has
a BR in it, like a primary partition.

> How do you make sure it is formed for the partition and knows were the
> proper stage 1.5, stage 2, and grub.conf or menu.lst are?

During installation, you tell it. Installation into the MBR vs. a BR
really has no difference in procedure. USE of course is different.
If GRUB is not installed into the MBR, then something else must
be used as the boot manager. For example, my machine can boot either
Windows XP or Fedora. I use the Windows XP boot manager to load GRUB
from the BR of my Linux partition.

Mike
-- 
p="p=%c%s%c;main(){printf(p,34,p,34);}";main(){printf(p,34,p,34);}
This message made from 100% recycled bits.
You have found the bank of Larn.
I can explain it for you, but I can't understand it for you.
I speak only for myself, and I am unanimous in that!




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