Re: [Gujin-users] 2.8.7 and gpt disk

[Richard K. <rk...@ya...>]

On Tue, 1/7/14, Etienne Lorrain wrote:
 
> So basically you can delete the ef02 partition, it will not
> be used.
> And anyway GPT partitions usually start at 2048, so keep it
> that way.
> So, because your USB key is booting without any other
> device,
> you have on the root partition (named 64bitisos) the two
> files
> "/boot/gujin.ebios" and "/boot/gujin.cmd".

I didn't know that. Thank you.
 
> So Gujin will propose you to boot either Debian Jessie or
> any of the *.iso
> files that Gujin will find (Gujin looks in the root
> filesystem and in /boot
> directory).
> Note the usual warning about booting an *.iso file: it does
> work, Gujin
> will pass control to the bootloader of the *.iso file
> (called the El-Torito
> bootloader, usually isolinux) and that bootloader will load
> the Linux
> kernel (or any other kernel) and run it successfully.
> Then that Linux kernel will want to find it's own filesystem
> on a physical
> CD/DVD-ROM or in some cases on a complete partition, but
> will not probe
> every *.iso files accessible to see if it is the right one.
> Some Linux installation *.iso image (for instance Debian
> install disks)
> do not need their "own filesystem" so they work with Gujin
> as you expect,
> but most *iso do not (they fail to run at this last stage).
> It is not possible for Gujin to tell ISOLINUX to add
> parameters to the Linux
> command line so that it knows which *.iso file to use, no
> such interface exists.

I did notice that iso's were failing at the last stage as you describe.
Thank you for clearing that up for me.

> What people have tried and used sucessfully is to copy the
> *.iso file
> in a partition and not have it as a file: create multiple
> partitions with
> a size bigger than your CD/DVD-ROM, for instance:
> - one Debian Jessie partition, where you can also add Debian
> installation
> netinstall cdrom
> - one swap if needed (for suspend to disk)
> - one Knoppix 5 Gb partition
> - one <insert a distribution name> 1 Gb partition
> - ... as many as you want.
> Even using GPT partitions, that is probably working without
> problem.

So that is the secret! Thank you.
 
> To be able to really boot *.iso files as you want to, a
> change has to be done
> in the initialisation scripts of the distribution itself: if
> no physical CD/DVD-ROM
> is found, if no partition is found, then use the information
> Gujin leaves
> (after INT13 vector) to get the right *.iso file to mount as
> root instead of
> crashing or running busybox.
> The patch do exist: I did even create a branch with all the
> stuff there:
> https://code.launchpad.net/~etienne-lorrain/casper/gujin
> It does work for me, but nobody did express any interest of
> supporting
> it or even testing it - so I did not push. It is true that
> this solution only
> works for Gujin (I still think it is better than crashing
> but...).

I will look at this also.
 
> I do not really like UUID but you can use them on Gujin
> default command
> line or file /boot/gujin.cmd, but I have nothing against
> GPT.

I prefer label myself.

> Not exactly, once you pressed the Shift-Fn you can manually
> change
> but that is not saved, what is saved locally is when you go
> to the end
> of Gujin menu (pressing space when Gujin is running and then
> the End
> key) you can edit the default command line with one of the
> options,
> and another option is to enable "write to disks".
> Alternatively you can edit /boot/gujin.cmd under Linux, I
> hope the syntax
> is simple enough.
>
> Etienne.

This, also, I did not know. You have helped me over several
difficulties with this mail. I am truly grateful that you have taken
so much time and have been so patient in explaining my many
mistakes!!

Once I have completed it all successfully I will report back to
this list.

Richard