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Re: Fedora tested in c't: grub missing feature



On Thu, Feb 5, 2009 at 9:02 PM, Jeff Spaleta <jspaleta gmail com> wrote:
2009/2/5 Thomas Bendler <ml bendler-net de>:
> ??? You are not able to figure out what a root partition is and what a boot
> partition is? The only thing you need is the root partition, the rest will
> be in /etc/fstab. And to find out what a root partition is, is not really
> complicated, all distributions will have a common set of directories in /,
> if not, they are not detected, but for most of the distributions this will
> work
I know a lot of things.. that the software in my computer does not
know. I'm smarter than my computer. You are smarter than your
computer.   What I know about the state of my filesystem is in fact
partly conceptualized in my human experience and not recoverable from
a blank slate reading of the contents of the filesystem.

I know that there is a difference between a human view and a computer based view on a problem ...

We are talking about teaching anaconda to know what I know in a
consistent and fast algorithmic way. if it takes more time for
anaconda to do it, by bruteforce disk searching of the filesystem
layout, than it takes for someone to edit the grub config by
hand...what the hell is the point. There's no win there.

... but you don't have to do a brute force thing. You only have to look at the partition, check the filesystem type (guess that comercial UNIX flavors don't use ext2/3/4, reiserfs, ...), check the directory layout for /boot, /etc, /bin, /sbin, /lib, /var, ... and you are pretty sure it's something Linux related. The next thing you need is /etc/fstab, /etc/lsb-release, /etc/redhat-release, ... and some way to find out what kernel in /boot/ is used for Grub or Lilo. That's it, not brute force, not an uncountable amount of files. Simple checking of some assumptions and if they are true, add the system to GRUB menu. The reason to do this is simply because it make life easier. And yes, it is possible to do it manually, I can also manually install the MBR. But the majority of users is not able to do this and will never be able to do this. So why not adding this support to the installation routine as other distributions also do. I don't talk about a hundred percent solution, this is only a quick way to do this and to add at least most of the distributions. The way to go is from my point of view the META data approach in GRUB, but this will take some time until this is really usable.

If we are going to find an implementation that works then we need to
think about it like a computer. We need to be dumb as dirt
(technically sand as we still have silicon based hardware), we need to
require explicit instructions...instead of making intuitive fuzzy
leaps of logic that involve heuristic parsing that relies on apriori
situational knowledge.

I know, I'm not only a system administrator, partly I'm also a programmer. But I think it could be done without much effort (as I described above).
 
I hand you a harddrive, I tell you it has 15 partitions sitting on the
disk, one of them is an ntfs partition and its the only partition
flagged as bootable.  List the set of explicit instructions that
detail how you would tell me find which of those partitions represent
a distinct linux operating system and how to generate a working grub
entry for each one of them.

Ok, short action list:

- Get partitions using parted, fdisk, whatever.
- Check for partition type (ext2/3/4, reiserfs, ...)
- Mount partitions that could be root file systems
- Check the directory layout for /boot, /etc, /bin, /sbin, /lib, /var, ... (what should be on root is in FHS)
- Check /etc/fstab, /etc/lsb-release, /etc/redhat-release, ...
- Check lilo.conf or menu.lst
- Add the found resources to own GRUB menu.lst

This part could also be packaged by a separate RPM to be able to let it run when the system is already installed but on another partition the kernel is changed (i.e. by an upgrade). It could also be called by firstboot instead of anaconda to make it more general usable. But, bottom line is, this is not complicated nor rocket since, it's only a question of doing it.

Regards, Thomas

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