12-11-2009
What Does Happen During Boot Process? - BIOS and MBR
I'm talking about boot process in multi-boot Linux perceptive.
Please tell me whether my explanation is right or wrong? If wrong, please explain.
"The BIOS checks the system and loads this initial bootstrapping code into
memory. This initial bootstrap code searches for an active partition and looks for a first sector of that active partition.
After that, bootstrap code gets whatever boot code (usually GRUB Stage 1) in the VBR and loads it in memory, so GRUB Stage 1 in this case overrides the MBR initial bootstrap that's in memory.
Once GRUB Stage 1 is in memory, it takes GRUB Stage 2 from /boot/ and loads it memory. Thus, GRUB Stage 2 overrides the GRUB Stage 1.
Now once GRUB Stage 2 is in memory, it presents an interface where the user
can select which OS to boot.
Once OS is selected, the GRUB stage 2 loads the selected Kernel into Memory, so the chosen OS Kernel overrides GRUB Stage 2.
Now this Kernel has the control and finishes the process. "
Thanks!
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LEARN ABOUT BSD
installgrub
installgrub(1M) installgrub(1M)
NAME
installgrub - install GRUB in a disk partition or a floppy
SYNOPSIS
/sbin/installgrub [-fm] stage1 stage2 raw-device
The installgrub command is an -only program. GRUB stands for GRand Unified Bootloader.
installgrub installs GRUB stage 1 and stage 2 files on the boot area of a disk partition. If you specify the -m option, installgrub
installs the stage 1 file on the master boot sector of the disk.
The installgrub command accepts the following options:
-f
Suppresses interaction when overwriting the master boot sector.
-m
Installs GRUB stage1 on the master boot sector interactively.
The installgrub command accepts the following operands:
stage1
The name of the GRUB stage 1 file.
stage2
The name of the GRUB stage 2 file.
raw-device
The name of the device onto which GRUB code is to be installed. It must be a character device that is readable and writable. For disk
devices, specify the slice where the GRUB menu file is located. (For Solaris it is the root slice.) For a floppy disk, it is
/dev/rdiskette.
Example 1: Installing GRUB on a Hard Disk Slice
The following command installs GRUB on a system where the root slice is c0d0s0:
example# /sbin/installgrub /boot/grub/stage1
/boot/grub/stage2 /dev/rdsk/c0d0s0
Example 2: Installing GRUB on a Floppy
The following command installs GRUB on a formatted floppy:
example# mount -F pcfs /dev/diskette /mnt
# mkdir -p /mnt/boot/grub
# cp /boot/grub/* /mnt/boot/grub
# umount /mnt
# cd /boot/grub
# /sbin/installgrub stage1 stage2 /dev/rdiskette
/boot/grub
Directory where GRUB files reside.
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
|Interface Stability |Evolving |
+-----------------------------+-----------------------------+
boot(1M), fdisk(1M), fmthard(1M), kernel(1M), attributes(5)
Installing GRUB on the master boot sector (-m option) overrides any boot manager currently installed on the machine. The system will always
boot the GRUB in the Solaris partition regardless of which fdisk partition is active.
24 May 2005 installgrub(1M)