Ubuntu – Booting Ubuntu with GRUB2: how to add boot entry to GRUB2

11.04bootbootloaderdual-bootgrub2

Last night, I decided to take the plunge, and install Ubuntu as complimentary part to my dual boot system (with Windows 7). Unfortunately, the entire process has been a struggle uphill, namely with getting the bootloader configured properly.

A short historical synopsis, for the full context of the situation:

  1. Generated and installed Ubuntu 11.04 x64 off of a USB drive setup on a Windows 7 machine. I had trouble getting the installer to even boot, until I learned I couldn't use my USB3.0 port. Switched to the USB2.0 port, continued with the install.

  2. I have a 1TB HDD that I split in half for the purpose of dual booting: 500GB partition for Windows 7, and a 500GB for Ubuntu (excluding the boot/swap file partitions). The Ubuntu partition was installed with the ext4 filesystem, and installation completed without any apparent problems, and was prompted to reboot.

  3. Upon rebooting, I got dumped into the old Windows boot loader, which immediately fired up Windows. I played around with a utility called EasyBCD to attempt to add a Linux entry to my newly installed partition, to no avail.

  4. Then, I booted Ubuntu straight off the USB drive, and installed GRUB2 onto the boot partition following the steps outlined here. I also ran the step ("update-grub") to generate a new 'grub.cfg' file, which added an entry to my old 'Windows 7' bootloader, but not one for my new Ubuntu partition! When I rebooted, the GRUB2 bootloader started successfully, but my Ubuntu was still unable to be found/booted under the list of available operating systems.

Anyone have any ideas how I should change/update this configuration such that it'll point to my new Ubuntu installation properly?

Some useful information…

"fdisk -l":

Disk /dev/sdd: 1000.2 GB, 1000204886016 bytes

255 heads, 63 sectors/track, 121601 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk identifier: 0xb209a592

  Device Boot      Start         End      Blocks   Id  System

  /dev/sdd1   *           1          13      102400    7  HPFS/NTFS

  Partition 1 does not end on cylinder boundary.

  /dev/sdd2              13       60555   486297600    7  HPFS/NTFS

  /dev/sdd3           60555      120143   478642176   83  Linux

  /dev/sdd4          120143      121602    11717633    5  Extended

  /dev/sdd5          120143      121602    11717632   82  Linux swap / Solaris

"grub.cfg" entries:

### BEGIN /etc/grub.d/30_os-prober ### menuentry "Windows 7 (loader) (on /dev/sdd1)" --class windows --class os {   insmod part_msdos   insmod ntfs     set root='(/dev/sdd,msdos1)'    search --no-floppy
--fs-uuid --set=root 08BAB5B0BAB59B20   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 ###

"boot_info_script output:

                  Boot Info Script 0.60    from 17 May 2011


============================= Boot Info Summary: ===============================

 => Windows is installed in the MBR of /dev/sda.
 => Windows is installed in the MBR of /dev/sdb.
 => Windows is installed in the MBR of /dev/sdc.
 => Grub2 (v1.99) is installed in the MBR of /dev/sdd and looks at sector 1 of 
    the same hard drive for core.img. core.img is at this location and looks 
    for (,msdos1)/grub on this drive.
 => Syslinux MBR (4.04 and higher) is installed in the MBR of /dev/sde.

sda1: __________________________________________________________________________

    File system:       ntfs
    Boot sector type:  Windows XP
    Boot sector info:   No errors found in the Boot Parameter Block.
    Operating System:  
    Boot files:        

sdb1: __________________________________________________________________________

    File system:       ntfs
    Boot sector type:  Windows Vista/7
    Boot sector info:   No errors found in the Boot Parameter Block.
    Operating System:  
    Boot files:        /bootmgr /Boot/BCD

sdb2: __________________________________________________________________________

    File system:       ntfs
    Boot sector type:  Windows Vista/7
    Boot sector info:   No errors found in the Boot Parameter Block.
    Operating System:  Windows 7
    Boot files:        /Windows/System32/winload.exe

sdc1: __________________________________________________________________________

    File system:       ntfs
    Boot sector type:  Windows XP
    Boot sector info:   No errors found in the Boot Parameter Block.
    Operating System:  
    Boot files:        

sdd1: __________________________________________________________________________

    File system:       ntfs
    Boot sector type:  Windows Vista/7
    Boot sector info:   No errors found in the Boot Parameter Block.
    Operating System:  
    Boot files:        /grub/grub.cfg /bootmgr /Boot/BCD /grub/core.img

sdd2: __________________________________________________________________________

    File system:       ntfs
    Boot sector type:  Windows Vista/7
    Boot sector info:   No errors found in the Boot Parameter Block.
    Operating System:  Windows 7
    Boot files:        /Windows/System32/winload.exe

sdd3: __________________________________________________________________________

    File system:       ext4
    Boot sector type:  -
    Boot sector info:  
    Operating System:  Ubuntu 11.04
    Boot files:        /boot/grub/grub.cfg /etc/fstab

sdd4: __________________________________________________________________________

    File system:       Extended Partition
    Boot sector type:  -
    Boot sector info:  

sdd5: __________________________________________________________________________

    File system:       swap
    Boot sector type:  -
    Boot sector info:  

sde1: __________________________________________________________________________

    File system:       vfat
    Boot sector type:  SYSLINUX 4.04 2011-04-18
    Boot sector info:   Syslinux looks at sector 8448 of /dev/sde1 for its 
                       second stage. SYSLINUX is installed in the  directory. 
                       The integrity check of the ADV area failed. No errors 
                       found in the Boot Parameter Block.
    Operating System:  
    Boot files:        /boot/grub/grub.cfg /syslinux/syslinux.cfg /ldlinux.sys

============================ Drive/Partition Info: =============================

Drive: sda _____________________________________________________________________

Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes

Partition  Boot  Start Sector    End Sector  # of Sectors  Id System

/dev/sda1                  63 1,953,520,064 1,953,520,002   7 NTFS / exFAT / HPFS


Drive: sdb _____________________________________________________________________

Disk /dev/sdb: 250.1 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders, total 488397168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes

Partition  Boot  Start Sector    End Sector  # of Sectors  Id System

/dev/sdb1               2,048       206,847       204,800   7 NTFS / exFAT / HPFS
/dev/sdb2    *        206,848   488,394,751   488,187,904   7 NTFS / exFAT / HPFS


Drive: sdc _____________________________________________________________________

Disk /dev/sdc: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes

Partition  Boot  Start Sector    End Sector  # of Sectors  Id System

/dev/sdc1                  63 1,953,520,064 1,953,520,002   7 NTFS / exFAT / HPFS


Drive: sdd _____________________________________________________________________

Disk /dev/sdd: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes

Partition  Boot  Start Sector    End Sector  # of Sectors  Id System

/dev/sdd1    *          2,048       206,847       204,800   7 NTFS / exFAT / HPFS
/dev/sdd2             206,848   972,802,047   972,595,200   7 NTFS / exFAT / HPFS
/dev/sdd3         972,802,048 1,930,086,399   957,284,352  83 Linux
/dev/sdd4       1,930,088,446 1,953,523,711    23,435,266   5 Extended
/dev/sdd5       1,930,088,448 1,953,523,711    23,435,264  82 Linux swap / Solaris


Drive: sde _____________________________________________________________________

Disk /dev/sde: 3926 MB, 3926949888 bytes
16 heads, 16 sectors/track, 29960 cylinders, total 7669824 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes

Partition  Boot  Start Sector    End Sector  # of Sectors  Id System

/dev/sde1    *          8,064     7,669,823     7,661,760   c W95 FAT32 (LBA)


"blkid" output: ________________________________________________________________

Device           UUID                                   TYPE       LABEL

/dev/loop0                                              squashfs   
/dev/sda1        36BA3C8CBA3C4A9F                       ntfs       Data Storage (Backup)
/dev/sdb1        90A09285A0927188                       ntfs       System Reserved
/dev/sdb2        88E09C67E09C5D6E                       ntfs       Old OS HDD
/dev/sdc1        1CEE7227EE71F8FA                       ntfs       Data Storage
/dev/sdd1        08BAB5B0BAB59B20                       ntfs       System Reserved
/dev/sdd2        30EEC43AEEC3F65E                       ntfs       Operating System
/dev/sdd3        fb62baf1-e6a7-4e0d-ada2-2efb52ab12fa   ext4       
/dev/sdd5        086c0085-650b-495f-b9e8-e7e637fac705   swap       
/dev/sde1        FC8F-97FE                              vfat       PENDRIVE

================================ Mount points: =================================

Device           Mount_Point              Type       Options

/dev/loop0       /rofs                    squashfs   (ro,noatime)
/dev/sde1        /cdrom                   vfat       (ro,noatime,fmask=0022,dmask=0022,codepage=cp437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)


============================= sdd1/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='(/dev/sdd,msdos5)'
search --no-floppy --fs-uuid --set=root 43000377-e88b-4373-975e-66146de829ce
if loadfont /usr/share/grub/unicode.pf2 ; then
  set gfxmode=auto
  load_video
  insmod gfxterm
fi
terminal_output gfxterm
insmod part_msdos
insmod ntfs
set root='(/dev/sdd,msdos1)'
search --no-floppy --fs-uuid --set=root 08BAB5B0BAB59B20
set locale_dir=($root)/grub/locale
set lang=en_US
insmod gettext
if [ "${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
### 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+ ###
### END /etc/grub.d/20_memtest86+ ###

### BEGIN /etc/grub.d/30_os-prober ###
# menuentry "Windows 7 (loader) (on /dev/sdb1)" --class windows --class os {
#   insmod part_msdos
#   insmod ntfs
#   set root='(/dev/sdb,msdos1)'
#   search --no-floppy --fs-uuid --set=root 90A09285A0927188
#   chainloader +1
# }
menuentry "Windows 7 (loader) (on /dev/sdd1)" --class windows --class os {
    insmod part_msdos
    insmod ntfs
    set root='(/dev/sdd,msdos1)'
    search --no-floppy --fs-uuid --set=root 08BAB5B0BAB59B20
    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 ###
--------------------------------------------------------------------------------

=================== sdd1: Location of files loaded by Grub: ====================

           GiB - GB             File                                 Fragment(s)

            ?? = ??             grub/core.img                                  1
            ?? = ??             grub/grub.cfg                                  1

=========================== sdd3/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 efi_gop
  insmod efi_uga
  insmod video_bochs
  insmod video_cirrus
}

insmod part_msdos
insmod ext2
set root='(/dev/sdd,msdos3)'
search --no-floppy --fs-uuid --set=root fb62baf1-e6a7-4e0d-ada2-2efb52ab12fa
if loadfont /usr/share/grub/unicode.pf2 ; then
  set gfxmode=auto
  load_video
  insmod gfxterm
fi
terminal_output gfxterm
insmod part_msdos
insmod ext2
set root='(/dev/sdd,msdos3)'
search --no-floppy --fs-uuid --set=root fb62baf1-e6a7-4e0d-ada2-2efb52ab12fa
set locale_dir=($root)/boot/grub/locale
set lang=en_US
insmod gettext
if [ "${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 2.6.38-8-generic' --class ubuntu --class gnu-linux --class gnu --class os {
    recordfail
    set gfxpayload=$linux_gfx_mode
    insmod part_msdos
    insmod ext2
    set root='(/dev/sdd,msdos3)'
    search --no-floppy --fs-uuid --set=root fb62baf1-e6a7-4e0d-ada2-2efb52ab12fa
    linux   /boot/vmlinuz-2.6.38-8-generic root=UUID=fb62baf1-e6a7-4e0d-ada2-2efb52ab12fa ro   quiet splash vt.handoff=7
    initrd  /boot/initrd.img-2.6.38-8-generic
}
menuentry 'Ubuntu, with Linux 2.6.38-8-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os {
    recordfail
    set gfxpayload=$linux_gfx_mode
    insmod part_msdos
    insmod ext2
    set root='(/dev/sdd,msdos3)'
    search --no-floppy --fs-uuid --set=root fb62baf1-e6a7-4e0d-ada2-2efb52ab12fa
    echo    'Loading Linux 2.6.38-8-generic ...'
    linux   /boot/vmlinuz-2.6.38-8-generic root=UUID=fb62baf1-e6a7-4e0d-ada2-2efb52ab12fa ro single 
    echo    'Loading initial ramdisk ...'
    initrd  /boot/initrd.img-2.6.38-8-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='(/dev/sdd,msdos3)'
    search --no-floppy --fs-uuid --set=root fb62baf1-e6a7-4e0d-ada2-2efb52ab12fa
    linux16 /boot/memtest86+.bin
}
menuentry "Memory test (memtest86+, serial console 115200)" {
    insmod part_msdos
    insmod ext2
    set root='(/dev/sdd,msdos3)'
    search --no-floppy --fs-uuid --set=root fb62baf1-e6a7-4e0d-ada2-2efb52ab12fa
    linux16 /boot/memtest86+.bin console=ttyS0,115200n8
}
### END /etc/grub.d/20_memtest86+ ###

### BEGIN /etc/grub.d/30_os-prober ###
menuentry "Windows 7 (loader) (on /dev/sdb1)" --class windows --class os {
    insmod part_msdos
    insmod ntfs
    set root='(/dev/sdb,msdos1)'
    search --no-floppy --fs-uuid --set=root 90A09285A0927188
    chainloader +1
}
menuentry "Windows 7 (loader) (on /dev/sdd1)" --class windows --class os {
    insmod part_msdos
    insmod ntfs
    set root='(/dev/sdd,msdos1)'
    search --no-floppy --fs-uuid --set=root 08BAB5B0BAB59B20
    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 ###
--------------------------------------------------------------------------------

=============================== sdd3/etc/fstab: ================================

--------------------------------------------------------------------------------
# /etc/fstab: static file system information.
#
# Use 'blkid -o value -s UUID' to print the universally unique identifier
# for a device; this may be used with UUID= as a more robust way to name
# devices that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    nodev,noexec,nosuid 0       0
# / was on /dev/sdd3 during installation
UUID=fb62baf1-e6a7-4e0d-ada2-2efb52ab12fa /               ext4    errors=remount-ro 0       1
# swap was on /dev/sdd5 during installation
UUID=086c0085-650b-495f-b9e8-e7e637fac705 none            swap    sw              0       0
--------------------------------------------------------------------------------

=================== sdd3: Location of files loaded by Grub: ====================

           GiB - GB             File                                 Fragment(s)

 476.025924683 = 511.128944640  boot/grub/grub.cfg                             1
 465.547851562 = 499.878199296  boot/initrd.img-2.6.38-8-generic               2
 686.000980377 = 736.587943936  boot/vmlinuz-2.6.38-8-generic                  1
 465.547851562 = 499.878199296  initrd.img                                     2
 686.000980377 = 736.587943936  vmlinuz                                        1

=========================== sde1/boot/grub/grub.cfg: ===========================

--------------------------------------------------------------------------------

if loadfont /boot/grub/font.pf2 ; then
    set gfxmode=auto
    insmod efi_gop
    insmod efi_uga
    insmod gfxterm
    terminal_output gfxterm
fi

set menu_color_normal=white/black
set menu_color_highlight=black/light-gray

menuentry "Try Ubuntu without installing" {
    set gfxpayload=keep
    linux   /casper/vmlinuz  file=/cdrom/preseed/ubuntu.seed boot=casper quiet splash --
    initrd  /casper/initrd.lz
}
menuentry "Install Ubuntu" {
    set gfxpayload=keep
    linux   /casper/vmlinuz  file=/cdrom/preseed/ubuntu.seed boot=casper only-ubiquity quiet splash --
    initrd  /casper/initrd.lz
}
menuentry "Check disc for defects" {
    set gfxpayload=keep
    linux   /casper/vmlinuz  boot=casper integrity-check quiet splash --
    initrd  /casper/initrd.lz
}
--------------------------------------------------------------------------------

========================= sde1/syslinux/syslinux.cfg: ==========================

--------------------------------------------------------------------------------
# D-I config version 2.0
include menu.cfg
default vesamenu.c32
prompt 0
timeout 50

# If you would like to use the new menu and be presented with the option to install or run from USB at startup, remove # from the following line. This line was commented out (by request of many) to allow the old menu to be presented and to enable booting straight into the Live Environment! 
# ui gfxboot bootlogo
--------------------------------------------------------------------------------

=================== sde1: Location of files loaded by Grub: ====================

           GiB - GB             File                                 Fragment(s)

            ?? = ??             boot/grub/grub.cfg                             1

================= sde1: Location of files loaded by Syslinux: ==================

           GiB - GB             File                                 Fragment(s)

            ?? = ??             ldlinux.sys                                    1
            ?? = ??             syslinux/gfxboot.c32                           1
            ?? = ??             syslinux/syslinux.cfg                          1
            ?? = ??             syslinux/vesamenu.c32                          1

============== sde1: Version of COM32(R) files used by Syslinux: ===============

 syslinux/gfxboot.c32               :  COM32R module (v4.xx)
 syslinux/vesamenu.c32              :  COM32R module (v4.xx)

=============================== StdErr Messages: ===============================

unlzma: Decoder error
/home/ubuntu/Desktop/boot_info_script.sh: line 1579: [: 2.73495e+09: integer expression expected

Best Answer

  • I would use the posted tutorial, procedure number 2 there. Before issuing the commands make sure that /dev/sdd is the intended 1TB drive.

    sudo mount /dev/sdd3 /mnt
    sudo grub-install --root-directory=/mnt/ /dev/sdd
    

    This will install the Grub loader to the beginning of the drive and to the /boot directory on sdd3.

    You don't need to run the update-grub section there. Then go to BIOS and mark the sdd drive as the primary boot device.