Re: How to boot alternative Debian version safely?

From: Anthony Campbell (ac_at_acampbell.org.uk)
Date: 02/11/05

  • Next message: Colin: "Re: running make-kpkg as a normal user" 
    Date: Fri, 11 Feb 2005 14:41:51 +0000
To: debian-user@lists.debian.org

    On 11 Feb 2005, Gene Heskett wrote:
    > >Thanks to all for replies. I've now managed to get Grub to access
    > > the partition but I get the following kernel error:
    > >
    > > Cannot open root device "hda7" or unknown block (0,0)
    > >
    > >My Grub entry is as follows:
    > >
    > >
    > >title Debian test system, kernel 2.6.8-1-386
    > >root (hd0,6)
    > >kernel /boot/vmlinuz-2.6.8-1-386 root=/dev/hda7 ro
    > >savedefault
    > >boot
    > >
    > >Anyone spot the error here?
    > >
    > >Anthony
    > Did your email agent wrap the above?
    >
    > In any event, you are specifying a seperate boot partition with the
    > line 'root (hd0,6)' above, so the next 'kernel' line s/b relative to
    > that. In other words:
    >
    > kernel /vmlinuz-2.6.8-1-386 ro root=/dev/hda7
    >
    > because there is not a /boot directory within the /boot partition,
    > then the path to vmlinuz becomes relative to the 'root (hd0,6)'
    > aka /boot partition. I assume your '/' partition is /dev/hda7?
    >
    > And what is the
    > savedefault
    > boot
    > ??
    >
    > The normal grub install has a few lines of comments above the actual
    > entries, and I'm wondering where they went.
    >

    Responding to you and Clive, here is my whole menu.lst. I don't know
    what savedefault and boot are doing but they were placed there by the
    automatic grub installation by Debian so I presumed they were needed.
    I just copied the existing entries and modified them to point at the new
    partition.

    The last entry on the list is for a kernel I compiled myself earlier and
    that does boot.

    # menu.lst - See: grub(8), info grub, update-grub(8)
    # grub-install(8), grub-floppy(8),
    # grub-md5-crypt, /usr/share/doc/grub
    # and /usr/share/doc/grub-doc/.

    ## default num
    # Set the default entry to the entry number NUM. Numbering starts from 0, and
    # the entry number 0 is the default if the command is not used.
    #
    # You can specify 'saved' instead of a number. In this case, the default entry
    # is the entry saved with the command 'savedefault'.
    default 0

    ## timeout sec
    # Set a timeout, in SEC seconds, before automatically booting the default entry
    # (normally the first entry defined).
    timeout 5

    # Pretty colours
    color cyan/blue white/blue

    ## password ['--md5'] passwd
    # If used in the first section of a menu file, disable all interactive editing
    # control (menu entry editor and command-line) and entries protected by the
    # command 'lock'
    # e.g. password topsecret
    # password --md5 $1$gLhU0/$aW78kHK1QfV3P2b2znUoe/
    # password topsecret

    #
    # examples
    #
    # title Windows 95/98/NT/2000
    # root (hd0,0)
    # makeactive
    # chainloader +1
    #
    # title Linux
    # root (hd0,1)
    # kernel /vmlinuz root=/dev/hda2 ro
    #

    #
    # Put static boot stanzas before and/or after AUTOMAGIC KERNEL LIST

    ### BEGIN AUTOMAGIC KERNELS LIST
    ## lines between the AUTOMAGIC KERNELS LIST markers will be modified
    ## by the debian update-grub script except for the default optons below

    ## DO NOT UNCOMMENT THEM, Just edit them to your needs

    ## ## Start Default Options ##
    ## default kernel options
    ## default kernel options for automagic boot options
    ## If you want special options for specifiv kernels use kopt_x_y_z
    ## where x.y.z is kernel version. Minor versions can be omitted.
    ## e.g. kopt=root=/dev/hda1 ro
    # kopt=root=/dev/hdb10 ro

    ## default grub root device
    ## e.g. groot=(hd0,0)
    # groot=(hd1,9)

    ## should update-grub create alternative automagic boot options
    ## e.g. alternative=true
    ## alternative=false
    # alternative=true

    ## should update-grub lock alternative automagic boot options
    ## e.g. lockalternative=true
    ## lockalternative=false
    # lockalternative=false

    ## altoption boot targets option
    ## multiple altoptions lines are allowed
    ## e.g. altoptions=(extra menu suffix) extra boot options
    ## altoptions=(recovery mode) single
    # altoptions=(recovery mode) single

    ## controls how many kernels should be put into the menu.lst
    ## only counts the first occurence of a kernel, not the
    ## alternative kernel options
    ## e.g. howmany=all
    ## howmany=7
    # howmany=all

    ## should update-grub create memtest86 boot option
    ## e.g. memtest86=true
    ## memtest86=false
    # memtest86=true

    ## ## End Default Options ##

    title Debian GNU/Linux, kernel 2.6.10-1-686
    root (hd1,9)
    kernel /boot/vmlinuz-2.6.10-1-686 root=/dev/hdb10 ro
    initrd /boot/initrd.img-2.6.10-1-686
    savedefault
    boot

    title Debian GNU/Linux, kernel 2.6.10-1-686 (recovery mode)
    root (hd1,9)
    kernel /boot/vmlinuz-2.6.10-1-686 root=/dev/hdb10 ro single
    initrd /boot/initrd.img-2.6.10-1-686
    savedefault
    boot

    title Debian test system, kernel 2.6.8-1-386
    root (hd0,6)
    kernel /boot/vmlinuz-2.6.8-1-386 root=/dev/hda7 ro
    savedefault
    boot

    title Debian GNU/Linux, kernel bzimage.268
    root (hd1,9)
    kernel /boot/bzimage.268 root=/dev/hdb10 ro
    savedefault
    boot
    ### END DEBIAN AUTOMAGIC KERNELS LIST 

    -- 
ac@acampbell.org.uk    ||  http://www.acampbell.org.uk for
using Linux GNU/Debian ||  weblog, book reviews, electronic  
Windows-free zone      ||  books and skeptical articles
-- 
To UNSUBSCRIBE, email to debian-user-REQUEST@lists.debian.org 
with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org
  • Next message: Colin: "Re: running make-kpkg as a normal user"

    Relevant Pages

    • editing savedefault entry in /boot/grub/menu.lst
      ... I am wanting to get a specific grub entry to be the default during the ... boot process, and I am not very experienced editing /boot/grub/menu.lst ... kernel 2.6.15-27-686 is consistently the entry that is booted ... ## by the debian update-grub script except for the default options below ...
      (Ubuntu)
    • Re: grub problem
      ... # Set the default entry to the entry number NUM. ... # Put static boot stanzas before and/or after ... AUTOMAGIC KERNEL LIST ... ## by the debian update-grub script except for the ...
      (Ubuntu)
    • grub locked
      ... I can still select a kernel choice with the cursor ... # Set the default entry to the entry number NUM. ... ## should update-grub create alternative automagic boot options ... ## should update-grub add savedefault to the default options ...
      (Debian-User)
    • 2.4.x to 2.6.y kernel
      ... and rebooted but now get a kernel panic with this kernel, ... # Set the default entry to the entry number NUM. ... # is the entry saved with the command 'savedefault'. ... # Put static boot stanzas before and/or after AUTOMAGIC KERNEL LIST ...
      (Debian-User)
    • grub problem
      ... corner, then after the timeout, grub prints the menu.lst entry of the ... selected kernel and the screen gets filled with white dots. ... # Put static boot stanzas before and/or after AUTOMAGIC KERNEL LIST ...
      (Ubuntu)