Re: GRUB problem (long, description of BOOT)
Wow, what a great explanation. I have read through it,
but am going to do another to make sure it's all taken
in. Thanks.
--- Mike McCarty <mike.mccarty@sbcglobal.net> wrote:
> Jeremy Merritt wrote:
> > I have been having a problem getting my GRUB
> > bootloader to return on boot. No matter what I do,
> it
> > keeps going to XP. I consulted with other people
> on
> > this list and got some good input. But have run
> into a
> > dead end again. Can someone analyze these steps
> and
> > tell me what I'm doing wrong, or what I need to do
> to
> > get the GRUB menu to return the way it was when I
> > first installed Debian:
> >
> > Steps so far:
> >
> > 1. Boot up with live CD (Knoppix)
> > 2. Activate shell and go root
> > 3. Mount /dev/hda5 as /mnt/hda5
> > 4. chroot /mnt/hda5 /bin/bash
> > 5. grub-install /dev/hda5 -- Reports successful
> > install but no results on bootup
>
> You installed GRUB as the boot record (BR) of one
> of your partitions (/dev/hda5). This will work fine,
> but it is
> not what the BIOS will load.
>
> I think you need a little more information about how
> boot is accomplished on IBM PC style computers. If
> you get that, then I think things will be much more
> clear. So, here is a brief tutorial on disc
> partitioning
> and how boot proceeds.
>
> Those who are familiar with this may either skip the
> rest of this message, or use it as a review, or
> criticize it for errors or omissions.
>
> Discs, to be used, must be formatted. The formatting
> takes place in levels. The lowest level (sometimes
> called low-level format) places tracks and sectors
> on
> each surface usable on the disc. Modern hard discs
> reserve
> one surface to hold tracking information alone, no
> data. Low-level formatting should not be done on
> modern
> hard discs except at the factory. Those of us who
> used to
> use MFM and RLL discs are glad for that.
>
> (Floppy discs have all three levels done at once
> by a single program, usually. This causes some
> confusion. The levels of formatting are actually
> done in passes even for floppies.)
>
> At the second level of formatting, the surface is
> divided into
> partitions (floppy discs have only one partition, so
> they
> have no partitioning to be done). Traditionally, the
> first
> record on the disc, the Master Boot Record (MBR)
> contains
> two parts: a small bootstrap program and a Partition
> Table
> (PT). Some consider the PT to be separate from the
> MBR.
> Also, traditionally, there may only be four (4)
> partitions defined.
> However, as time went by discs grew larger, and a
> percieved
> need for more partitions grew as well. So the
> concept of
> a Primary Partition and an Extended Partition was
> developed.
> There could be only four (4) Primary Partitions, but
> only one (1) Extended Partition. If an Extended
> Partition
> existed, it used up one of the entries, so only up
> to three
> (3) Primary Partitions could then be defined. The PT
> uses
> physical addresses (head, track [or cylinder], and
> sector).
>
> Within the Extended Partition, Logical Partitions
> (also
> called Logical Discs or Volumes) could be created.
> Primary
> Partitions also contain Volumes, but only one per
> partition.
>
> Each Partition has a type (OS, more or less) and a
> status.
> The status could be either Bootable (also called
> Active) or
> non-bootable (Inactive). Only up to one (1)
> partition may be in
> an Active state, and if so, it must be a Primary
> Partition.
>
> A floppy disc is a single Volume, hard discs
> may have up to one Volume per Primary Partition, and
> any number of Volumes (logical partitions or logical
> discs) in an extended partition. Each Volume has
> a Boot Record (BR) also called BIOS Parameter Block
> (BPB).
> Technically, the BPB is actually a part of the BR,
> in
> somewhat the same way the PT is part of the MBR.
>
> The BR contains a description of the logical layout
> of the Volume,
> like how many reserved sectors there are before the
> data area,
> how many logical sectors there are, etc. The BR uses
> logical disc
> addressing (logical sector number).
>
> The top level of format is the File System (FS). The
> file system uses allocatable units for addressing.
> Exactly
> what an allocatable unit is depends on what FS is
> being
> used. Usually the FS presents an Application
> Programming
> Interface (API) which uses File Addressing
> (directories,
> files, and records within file).
>
> >
> > fdisk -l information (hda5=Mandrake, hdb2=Debian,
> > system is booting from hda1=XP):
> >
> > Disk /dev/hda: 40.0 GB, 40020664320 bytes
>
> This is your first disc.
>
> > 255 heads, 63 sectors/track, 4865 cylinders
> > Units = cylinders of 16065 * 512 = 8225280 bytes
> >
> > Device Boot Start End Blocks Id System
> > /dev/hda1 * 1 2433 19543041 7 HPFS/NTFS
>
> Here is your primary partition which is active.
>
> > /dev/hda2 2434 4865 19535040 5 Extended
>
> This is your extended partition.
>
> > /dev/hda5 2434 3197 6136798+ 83 Linux
> > /dev/hda6 3198 3337 1124518+ 82 Linux swap
> > /dev/hda7 3338 4865 12273628+ 83 Linux
>
> These are volumes inside your extended partition.
> Each of them may be treated as a partition.
>
>
> > Disk /dev/hdb: 61.4 GB, 61492838400 bytes
>
> This is your second disc.
>
> > 255 heads, 63 sectors/track, 7476 cylinders
> > Units = cylinders of 16065 * 512 = 8225280 bytes
> >
> > Device Boot Start End Blocks Id System
> > /dev/hdb1 1 3188 25607578+ c W95 FAT32 (LBA)
>
> This is a primary partition, not bootable.
> (LBA = Linear Block Addressing, which means
> that your BIOS is translating logical disc
> addresses [sector number only] into physical
> addresses [head, cylinder, sector] for you.)
>
> > /dev/hdb2 * 3189 7298 33013575 83 Linux
>
> This is a primary partition, which is active.
>
> > /dev/hdb3 7299 7476 1429785 5 Extended
>
> This is an extended partition.
>
> > /dev/hdb5 7299 7476 1429753+ 82 Linux swap
>
> This is a logical volume inside your extended
> partition.
>
> >
> > Disk /dev/hdd: 30.0 GB, 30020272128 bytes
>
> This is your fourth disc. (Where is 3? Possibly
> your CD reader.)
>
> > 255 heads, 63 sectors/track, 3649 cylinders
> > Units = cylinders of 16065 * 512 = 8225280 bytes
> >
> > Device Boot Start End Blocks Id System
> > /dev/hdd1 * 1 3649 29310561 83 Linux
>
=== message truncated ===
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