Bootloader

Bootloader adalah aplikasi untuk mengatur, memuat, dan memanggil Linux saat pertama kali komputer dinyalakan. Dulu linux mempunyai LILO (Linux Loader), tapi sekarang bootloader yang banyak digunakan adalah Grub Bootaloader. Fungsi bootloader bukan hanya dilinux, tapi juga bisa memudahkan untuk memanggil Sistem Operasi lain yang sudah ada dikomputer anda, seperti Windows,Macintos, dsb. Istilah ini disebut dual Boot. secara default bootloader saat installasi diinstall tanpa menimpa patisi windows. Bootloader boot akan menempati MBR ( Master Boot Record ) sehingga partisi windows sebelum partisi linux dimuat akan dimuat juga dalam bootloader Grub. Maka User dapat memilih sistem Operasi yang akan dijalankan Windows or Linux.

Booloader dapat dikofigurasi pada konsole atau Shell. file kofigurasi GRUB terletak pada /boot/grub/menu.lst. Jika ingin melakukan editing pada Bootloader Grub maka ketiklah pada terminal salah satu editor teks seperti vi or emacs.

$sudo vi /boot/grub/grub.cfg

Tapi jika anda hanya melihat file Grub tanpa merubahnya ketiklah :

$cat boot/grub/grub.cfg

bemyself@bemyself-G31M:~$ cat /boot/grub/grub.cfg
#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###
if [ -s $prefix/grubenv ]; then
  set have_grubenv=true
  load_env
fi
set default="0"
if [ "${prev_saved_entry}" ]; then
  set saved_entry="${prev_saved_entry}"
  save_env saved_entry
  set prev_saved_entry=
  save_env prev_saved_entry
  set boot_once=true
fi

function savedefault {
  if [ -z "${boot_once}" ]; then
    saved_entry="${chosen}"
    save_env saved_entry
  fi
}

function recordfail {
  set recordfail=1
  if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi
}

function load_video {
  insmod vbe
  insmod vga
  insmod video_bochs
  insmod video_cirrus
}

insmod part_msdos
insmod ext2
set root='(hd0,msdos7)'
search --no-floppy --fs-uuid --set=root dd71003f-079d-4ecd-85c6-c0b692454216
if loadfont /usr/share/grub/unicode.pf2 ; then
  set gfxmode=auto
  load_video
  insmod gfxterm
  insmod part_msdos
  insmod ext2
  set root='(hd0,msdos7)'
  search --no-floppy --fs-uuid --set=root dd71003f-079d-4ecd-85c6-c0b692454216
  set locale_dir=($root)/boot/grub/locale
  set lang=en_US
  insmod gettext
fi
terminal_output gfxterm
if [ "${recordfail}" = 1 ]; then
  set timeout=-1
else
  set timeout=10
fi
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/05_debian_theme ###
set menu_color_normal=white/black
set menu_color_highlight=black/light-gray
if background_color 44,0,30; then
  clear
fi
### END /etc/grub.d/05_debian_theme ###

### BEGIN /etc/grub.d/10_linux ###
if [ ${recordfail} != 1 ]; then
  if [ -e ${prefix}/gfxblacklist.txt ]; then
    if hwmatch ${prefix}/gfxblacklist.txt 3; then
      if [ ${match} = 0 ]; then
        set linux_gfx_mode=keep
      else
        set linux_gfx_mode=text
      fi
    else
      set linux_gfx_mode=text
    fi
  else
    set linux_gfx_mode=keep
  fi
else
  set linux_gfx_mode=text
fi
export linux_gfx_mode
if [ "$linux_gfx_mode" != "text" ]; then load_video; fi
menuentry 'Ubuntu, with Linux 3.0.0-12-generic' --class ubuntu --class gnu-linux --class gnu --class os {
    recordfail
    set gfxpayload=$linux_gfx_mode
    insmod gzio
    insmod part_msdos
    insmod ext2
    set root='(hd0,msdos7)'
    search --no-floppy --fs-uuid --set=root dd71003f-079d-4ecd-85c6-c0b692454216
    linux    /boot/vmlinuz-3.0.0-12-generic root=UUID=dd71003f-079d-4ecd-85c6-c0b692454216 ro   quiet splash vt.handoff=7
    initrd    /boot/initrd.img-3.0.0-12-generic
}
menuentry 'Ubuntu, with Linux 3.0.0-12-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os {
    recordfail
    insmod gzio
    insmod part_msdos
    insmod ext2
    set root='(hd0,msdos7)'
    search --no-floppy --fs-uuid --set=root dd71003f-079d-4ecd-85c6-c0b692454216
    echo    'Loading Linux 3.0.0-12-generic ...'
    linux    /boot/vmlinuz-3.0.0-12-generic root=UUID=dd71003f-079d-4ecd-85c6-c0b692454216 ro recovery nomodeset
    echo    'Loading initial ramdisk ...'
    initrd    /boot/initrd.img-3.0.0-12-generic
}
### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/20_linux_xen ###
### END /etc/grub.d/20_linux_xen ###

### BEGIN /etc/grub.d/20_memtest86+ ###
menuentry "Memory test (memtest86+)" {
    insmod part_msdos
    insmod ext2
    set root='(hd0,msdos7)'
    search --no-floppy --fs-uuid --set=root dd71003f-079d-4ecd-85c6-c0b692454216
    linux16    /boot/memtest86+.bin
}
menuentry "Memory test (memtest86+, serial console 115200)" {
    insmod part_msdos
    insmod ext2
    set root='(hd0,msdos7)'
    search --no-floppy --fs-uuid --set=root dd71003f-079d-4ecd-85c6-c0b692454216
    linux16    /boot/memtest86+.bin console=ttyS0,115200n8
}
### END /etc/grub.d/20_memtest86+ ###

### BEGIN /etc/grub.d/30_os-prober ###
menuentry "Microsoft Windows XP Professional (on /dev/sda1)" --class windows --class os {
    insmod part_msdos
    insmod ntfs
    set root='(hd0,msdos1)'
    search --no-floppy --fs-uuid --set=root C028199D2819940E
    drivemap -s (hd0) ${root}
    chainloader +1
}
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###

### BEGIN /etc/grub.d/41_custom ###
if [ -f  $prefix/custom.cfg ]; then
  source $prefix/custom.cfg;
fi
### END /etc/grub.d/41_custom ###
bemyself@bemyself-G31M:~$

Tulisan diatas merupakan konfigurasi GRUB bootloader


sumber : Kindarto Asdani, 2011, 123 Tip Trik Mengoptimalisasi Ubuntu,Jakarta: Andi