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Re: How to boot alternative Debian version safely?



On (11/02/05 14:41), Anthony Campbell wrote:
> 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
> 

I think you need to move the next entry to below the automatic
kernels list.  I don't think you can realistically expect grub to
autoconfigure kernels for two different systems on one grub installation.  

Regards

Clive
> 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
> 

-- 
www.clivemenzies.co.uk ...
...strategies for business




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