Does grub2 solve this problem I am having with grub1? RE: usbsticks.

Does grub2 solve this problem I am having with grub1? RE: usbsticks.

[Paul Elliott]

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I am having this problem with grub1 and I wonder if grub2
solves it.

The problem is at the time I setup the grub system I do
not know what device my usbstick will be on.

To be explicit I am writting menu.lst for a grub
booter on a usbstick and I do not know what to
put for X in the following statement:

root (hdX,0)


The usb stick will be used on many different computers
with different number of hard drives. Therefore X
actually varries.

Is there a solution for this in grub2? That is in writting
the equivalent of menu.lst for grub2, is there a way to
specify "the device that my menu.lst and my stage files
are on" without knowing in advance where that will be?

If so, how would one do this in grub2?

-- 
Paul Elliott                       1(512)837-1096
pelliott@io.com                    PMB 181, 11900 Metric Blvd Suite J
http://www.io.com/~pelliott/pme/   Austin TX 78758-3117

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Re: Does grub2 solve this problem I am having with grub1? RE: usbsticks.

[Pavel Roskin]

On Thu, 2008-01-31 at 10:08 -0600, Paul Elliott wrote:

> Is there a solution for this in grub2? That is in writting
> the equivalent of menu.lst for grub2, is there a way to
> specify "the device that my menu.lst and my stage files
> are on" without knowing in advance where that will be?
> 
> If so, how would one do this in grub2?

I think that device will be in the root variable.  You'll just need to
use paths without the device name, e.g.

linux /boot/vmlinuz
initrd /boot/initrd.img

-- 
Regards,
Pavel Roskin

Re: Does grub2 solve this problem I am having with grub1? RE: usbsticks.

[Paul Elliott]

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On Thu, Jan 31, 2008 at 11:58:01AM -0500, Pavel Roskin wrote:
> On Thu, 2008-01-31 at 10:08 -0600, Paul Elliott wrote:
> 
> > Is there a solution for this in grub2? That is in writting
> > the equivalent of menu.lst for grub2, is there a way to
> > specify "the device that my menu.lst and my stage files
> > are on" without knowing in advance where that will be?
> > 
> > If so, how would one do this in grub2?
> 
> I think that device will be in the root variable.  You'll just need to
> use paths without the device name, e.g.
> 
> linux /boot/vmlinuz
> initrd /boot/initrd.img
> 

Ok, but how do I say the same device as I am in now, but the
3rd partiton, rather than the first.

How do I say (hdX,3) where X in the device I am in now? And
X may vary at boot time depending on the number of hard disks
on the target system?



-- 
Paul Elliott                       1(512)837-1096
pelliott@io.com                    PMB 181, 11900 Metric Blvd Suite J
http://www.io.com/~pelliott/pme/   Austin TX 78758-3117

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Re: Does grub2 solve this problem I am having with grub1? RE: usbsticks.

[Pavel Roskin]

On Thu, 2008-01-31 at 22:34 -0600, Paul Elliott wrote:

> Ok, but how do I say the same device as I am in now, but the
> 3rd partiton, rather than the first.
> 
> How do I say (hdX,3) where X in the device I am in now? And
> X may vary at boot time depending on the number of hard disks
> on the target system?

I wish I knew the answer.  There is some undocumented scripting
functionality, but it doesn't appear to be capable of that yet.  Perhaps
there should be a "boot_device" variable for that purpose.

-- 
Regards,
Pavel Roskin

Re: Does grub2 solve this problem I am having with grub1? RE: usbsticks.

[Paul Elliott]

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On Thu, Jan 31, 2008 at 11:50:37PM -0500, Pavel Roskin wrote:
> On Thu, 2008-01-31 at 22:34 -0600, Paul Elliott wrote:
> 
> > Ok, but how do I say the same device as I am in now, but the
> > 3rd partiton, rather than the first.
> > 
> > How do I say (hdX,3) where X in the device I am in now? And
> > X may vary at boot time depending on the number of hard disks
> > on the target system?
> 
> I wish I knew the answer.  There is some undocumented scripting
> functionality, but it doesn't appear to be capable of that yet.  Perhaps
> there should be a "boot_device" variable for that purpose.
> 

As usb devices become more used this will be an important problem.

For example, I want to create a usb flash drive for use in an
installfest, for people with no CD or floppy.

Partition 1 will have the kernel and initrd for the Fedora installation
process.

Partition 2 will have the same for Opensuse.

Partiton 3 the same for Mandriva.

Partiton 4 ubuntu.

How do I write a menu.lst to boot these different kernels with
different parameters, and partitions? I do not know which device the
usbstick will be at boot time, because the target systems have
different number of hard disks.

As matters now stand, there is no way to do it, and you seem to be
telling me the problem is not fixed with grub2!

It is easy to think of many analogous problems, in the comercial world.



-- 
Paul Elliott                       1(512)837-1096
pelliott@io.com                    PMB 181, 11900 Metric Blvd Suite J
http://www.io.com/~pelliott/pme/   Austin TX 78758-3117

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Re: Does grub2 solve this problem I am having with grub1? RE: usbsticks.

[Pavel Roskin]

On Fri, 2008-02-01 at 06:59 -0600, Paul Elliott wrote:

> As usb devices become more used this will be an important problem.

Are you sure that it will be seen as a separate device?

> For example, I want to create a usb flash drive for use in an
> installfest, for people with no CD or floppy.

That would be great.

> Partition 1 will have the kernel and initrd for the Fedora installation
> process.
> 
> Partition 2 will have the same for Opensuse.
> 
> Partiton 3 the same for Mandriva.
> 
> Partiton 4 ubuntu.
> 
> How do I write a menu.lst to boot these different kernels with
> different parameters, and partitions? I do not know which device the
> usbstick will be at boot time, because the target systems have
> different number of hard disks.

Would not the boot device be hd0?

> As matters now stand, there is no way to do it, and you seem to be
> telling me the problem is not fixed with grub2!

Even if I add boot_device now, there is an issue with the variable
expansion, to that ($boot_device,3) would not expand to a valid device
name.

One possible approach would be to use LVM (Logical Volume Manager) -
it's supported by grub2.  You could install grub on a small boot
partition and allocate the rest to as an LVM partition, that would be
split into volumes.  Then you could refer to the volumes by name.

> It is easy to think of many analogous problems, in the comercial world.

I agree.

-- 
Regards,
Pavel Roskin

Re: Does grub2 solve this problem I am having with grub1? RE: usbsticks.

[Paul Elliott]

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On Fri, Feb 01, 2008 at 12:25:30PM -0500, Pavel Roskin wrote:
> On Fri, 2008-02-01 at 06:59 -0600, Paul Elliott wrote:
> 
> > As usb devices become more used this will be an important problem.
> 
> Are you sure that it will be seen as a separate device?
> 
> > For example, I want to create a usb flash drive for use in an
> > installfest, for people with no CD or floppy.
> 
> That would be great.
> 
> > Partition 1 will have the kernel and initrd for the Fedora installation
> > process.
> > 
> > Partition 2 will have the same for Opensuse.
> > 
> > Partiton 3 the same for Mandriva.
> > 
> > Partiton 4 ubuntu.
> > 
> > How do I write a menu.lst to boot these different kernels with
> > different parameters, and partitions? I do not know which device the
> > usbstick will be at boot time, because the target systems have
> > different number of hard disks.
> 
> Would not the boot device be hd0?

No, usually the first hard disk is hd0, the second hard disk
is hd1, and the usb sticks come after that. At least that is
how it works under my computer. Usually it is because the number
of hard disks differ that causes you not to know which device
the usb stick is.

The Problem does not have to involve usbsticks. One can imagine
a situation in which to device one is booting from is always
the first scsi disk. But some computers have one or more IDE
drives wich are recognized by the bios as hd0, hd1, ect.

The Fedora/RedHat kernels/initrd have this feature where you can
specify the root partition to the kernel/initrd by volume label. You
can say 'root=LABEL=/' to tell the kernel to find the partition with the
label '/' and use that as the root partition. This feature does not
require LVN. The kernel/initrd will check all the partitons and find
the one lableled '/'.

But this does not have anything to do with how one
specifies partitions to grub. But perhaps grub should adopt a similar
feature.


> 
> > As matters now stand, there is no way to do it, and you seem to be
> > telling me the problem is not fixed with grub2!
> 
> Even if I add boot_device now, there is an issue with the variable
> expansion, to that ($boot_device,3) would not expand to a valid device
> name.
> 
> One possible approach would be to use LVM (Logical Volume Manager) -
> it's supported by grub2.  You could install grub on a small boot
> partition and allocate the rest to as an LVM partition, that would be
> split into volumes.  Then you could refer to the volumes by name.
> 

This seems a long way to drag the cat around the barn. Or this
would be like kicking dead whales down the beach. One should
not have to invoke the complexity of LVN just so one can specify
partitions.


> > It is easy to think of many analogous problems, in the comercial world.
> 
> I agree.
> 

-- 
Paul Elliott                       1(512)837-1096
pelliott@io.com                    PMB 181, 11900 Metric Blvd Suite J
http://www.io.com/~pelliott/pme/   Austin TX 78758-3117

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Re: Does grub2 solve this problem I am having with grub1? RE: usbsticks.

[Pavel Roskin]

On Fri, 2008-02-01 at 12:44 -0600, Paul Elliott wrote:
> > One possible approach would be to use LVM (Logical Volume Manager) -
> > it's supported by grub2.  You could install grub on a small boot
> > partition and allocate the rest to as an LVM partition, that would be
> > split into volumes.  Then you could refer to the volumes by name.
> > 
> 
> This seems a long way to drag the cat around the barn. Or this
> would be like kicking dead whales down the beach. One should
> not have to invoke the complexity of LVN just so one can specify
> partitions.

OK, let's fix GRUB.

As for the expansion issue, I think I see how to fix it.
grub_script_arg_add() should append expanded variables to the last
argument, rather than allocate a new argument, unless the new argument
is separated by spaces from the previous one.

GRUB_SCRIPT_ARG_TYPE_STR and GRUB_SCRIPT_ARG_TYPE_VAR are "write only".
I think we should discard grub_script_arg_type_t or use it to keep track
of spaces in the input.

As for the "boot_device", it could be set in the same place as "root",
namely in grub_set_root_dev() in kern/main.c.

-- 
Regards,
Pavel Roskin

Re: Does grub2 solve this problem I am having with grub1? RE: usbsticks.

[Paul Elliott]

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On Fri, Feb 01, 2008 at 03:14:51PM -0500, Pavel Roskin wrote:
> On Fri, 2008-02-01 at 12:44 -0600, Paul Elliott wrote:
> > > One possible approach would be to use LVM (Logical Volume Manager) -
> > > it's supported by grub2.  You could install grub on a small boot
> > > partition and allocate the rest to as an LVM partition, that would be
> > > split into volumes.  Then you could refer to the volumes by name.
> > > 
> > 
> > This seems a long way to drag the cat around the barn. Or this
> > would be like kicking dead whales down the beach. One should
> > not have to invoke the complexity of LVN just so one can specify
> > partitions.
> 
> OK, let's fix GRUB.
> 
> As for the expansion issue, I think I see how to fix it.
> grub_script_arg_add() should append expanded variables to the last
> argument, rather than allocate a new argument, unless the new argument
> is separated by spaces from the previous one.
> 
> GRUB_SCRIPT_ARG_TYPE_STR and GRUB_SCRIPT_ARG_TYPE_VAR are "write only".
> I think we should discard grub_script_arg_type_t or use it to keep track
> of spaces in the input.
> 
> As for the "boot_device", it could be set in the same place as "root",
> namely in grub_set_root_dev() in kern/main.c.
> 

Ok, you are well into grub2 internals, and beond the areas I am
familiar with.

I am glad the problem is being addressed and glad I could be
helpfull in pointing out the problem.

When grub2 is finished, I will look in the manual and see what
syntax I need to use to solve problems like this.




-- 
Paul Elliott                       1(512)837-1096
pelliott@io.com                    PMB 181, 11900 Metric Blvd Suite J
http://www.io.com/~pelliott/pme/   Austin TX 78758-3117

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Re: Does grub2 solve this problem I am having with grub1? RE: usbsticks.

[Robert Millan]

On Fri, Feb 01, 2008 at 03:45:40PM -0600, Paul Elliott wrote:
> 
> When grub2 is finished, I will look in the manual and see what
> syntax I need to use to solve problems like this.

Finished or not, we won't have a manual untill someone volunteers to work on
it.

-- 
Robert Millan

<GPLv2> I know my rights; I want my phone call!
<DRM> What use is a phone call… if you are unable to speak?
(as seen on /.)

Re: Does grub2 solve this problem I am having with grub1? RE: usbsticks.

[Yoshinori K. Okuji]

On Friday 01 February 2008 19:44, Paul Elliott wrote:
> > Would not the boot device be hd0?
>
> No, usually the first hard disk is hd0, the second hard disk
> is hd1, and the usb sticks come after that. At least that is
> how it works under my computer. Usually it is because the number
> of hard disks differ that causes you not to know which device
> the usb stick is.

Nope. If you boot from a usb disk, it is always hd0. This is the PC BIOS.

> The Problem does not have to involve usbsticks. One can imagine
> a situation in which to device one is booting from is always
> the first scsi disk. But some computers have one or more IDE
> drives wich are recognized by the bios as hd0, hd1, ect.

No. If you boot from a SCSI disk, it is hd0. All IDE disks are shifted to hd1, 
hd2, etc.

> The Fedora/RedHat kernels/initrd have this feature where you can
> specify the root partition to the kernel/initrd by volume label. You
> can say 'root=LABEL=/' to tell the kernel to find the partition with the
> label '/' and use that as the root partition. This feature does not
> require LVN. The kernel/initrd will check all the partitons and find
> the one lableled '/'.
>
> But this does not have anything to do with how one
> specifies partitions to grub. But perhaps grub should adopt a similar
> feature.

It is already there. GRUB 2 already supports setting a root based on a 
filesystem label or a path.

Okuji

Re: Does grub2 solve this problem I am having with grub1? RE: usbsticks.

[Paul Elliott]

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On Sat, Feb 02, 2008 at 01:11:18PM +0100, Yoshinori K. Okuji wrote:
> 
> It is already there. GRUB 2 already supports setting a root based on a 
> filesystem label or a path.
> 

What is the syntax? How do I set it up? Are there example grub2 setups?



-- 
Paul Elliott                       1(512)837-1096
pelliott@io.com                    PMB 181, 11900 Metric Blvd Suite J
http://www.io.com/~pelliott/pme/   Austin TX 78758-3117

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Re: Does grub2 solve this problem I am having with grub1? RE: usbsticks.

[Pavel Roskin]

On Sat, 2008-02-02 at 08:34 -0600, Paul Elliott wrote:
> On Sat, Feb 02, 2008 at 01:11:18PM +0100, Yoshinori K. Okuji wrote:
> > 
> > It is already there. GRUB 2 already supports setting a root based on a 
> > filesystem label or a path.

Indeed!  That's much easier that LVM :-)

> What is the syntax? How do I set it up? Are there example grub2 setups?

grub> help search
Usage: search [-f|-l|-s] NAME
Search devices by a file or a filesystem label. If --set is specified,
the first device found is set to a variable. If no variable name is
specified, "root" is used.

-f, --file                search devices by a file (default)
-l, --label               search devices by a filesystem label
-s, --set=VAR             set a variable to the first device found
-h, --help                display this help and exit
-u, --usage               display the usage of this command and exit
grub>


That means, you can use unique labels like "usbstick-fedora8" and then
use:

search -f usbstick-fedora8
linux /boot/vmlinuz-2.6.24-f8
initrd /boot/initrd-2.6.24-f8.img

or something like that.

-- 
Regards,
Pavel Roskin

Re: Does grub2 solve this problem I am having with grub1? RE: usbsticks.

[Pavel Roskin]

On Sun, 2008-02-03 at 00:58 -0500, Pavel Roskin wrote:

> grub> help search
> Usage: search [-f|-l|-s] NAME
> Search devices by a file or a filesystem label. If --set is specified,
> the first device found is set to a variable. If no variable name is
> specified, "root" is used.

Actually, I was wrong to assume that "root" is used even if "--set" is
not specified.

> That means, you can use unique labels like "usbstick-fedora8" and then
> use:
> 
> search -f usbstick-fedora8

That should be:

search -f usbstick-fedora8 -s

-- 
Regards,
Pavel Roskin

Re: Does grub2 solve this problem I am having with grub1? RE: usbsticks.

[Paul Elliott]

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On Sat, Feb 02, 2008 at 01:11:18PM +0100, Yoshinori K. Okuji wrote:
> 
> Nope. If you boot from a usb disk, it is always hd0. This is the PC BIOS.
> 

I just tried this on my nephew's Dell. Durring boot I pushed F12
to bring up the boot device menu. I choose usb device.

I had a usbstick with super grub disk on it.

When it booted, it showed the boot device was hd1.



-- 
Paul Elliott                       1(512)837-1096
pelliott@io.com                    PMB 181, 11900 Metric Blvd Suite J
http://www.io.com/~pelliott/pme/   Austin TX 78758-3117

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