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so, this new install completed yesterday (a very brave stage 3 with GRP packages), is doing weird stuff. With the grub install 0.96-r1 when I boot the system it looks ...
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  1. #1
    Just Joined! bigjohn's Avatar
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    Another Weird problem - with grub


    so, this new install completed yesterday (a very brave stage 3 with GRP packages), is doing weird stuff.

    With the grub install 0.96-r1 when I boot the system it looks like it's starting normally, but instead of giving me a title etc, I just get a blinking cursor, and if I hit enter, it boots.

    So today, after doing the usual emerge -uD world, it had installed the later kernel version 2.6.11-gentoo-r8 and the grub.conf now looks like this

    default 0
    timeout 30
    splashimage=(hd0,0) /grub/splash.xpm.gz

    title=Gentoo Linux 2.6.11-r8
    root (hd0,0)
    kernel /kernel-2.6.11-gentoo-r8 root=/dev/ram0 init=/linuxrc ramdisk=8192 real_root=/dev/hda3 udev vga=0x317 splash=verbose
    initrd /initrd-2.6.11-gentoo-r8

    title=Gentoo Linux 2.6.11-r3
    root (hd0,0)
    kernel /kernel-2.6.11-gentoo-r3 root=/dev/ram0 init=/linuxrc ramdisk=8192 real_root=/dev/hda3 udev vga=0x317 splash=verbose
    initrd /initrd-2.6.11-gentoo-r3
    and when I boot the system now, I still get the same thing, but if I hit enter, I get a really strange message about invalid video modes, If I either wait 10 seconds or hit enter again, it looks like it's starting to boot but then stops with the message
    >>Block device /dev/hda3 is not a valid root device
    >>The root block device is unspecified or not detected

    Please specify a device to boot, or "Shell" for a shell.....
    It's exactly the same partition as the earlier 2.6.11-gentoo-r3 kernel i.e. /dev/hda3

    Can anyone explain what the hells going on here, and how do I correct it ?

    regards

    John

  2. #2
    Linux User Stefann's Avatar
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    GURB is trying to boot from hd(0,0)[master disk, first partition], as stated in the first line of each config, but the path is /dev/hda3(usually master disk, third partition), are you sure that /dev/hda3 is the first physical partition on the disk?
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    Quote Originally Posted by Stefann
    GURB is trying to boot from hd(0,0)[master disk, first partition], as stated in the first line of each config, but the path is /dev/hda3(usually master disk, third partition), are you sure that /dev/hda3 is the first physical partition on the disk?
    I don't understand what you mean?

    the partitions are /dev/hda1 which is /boot, /dev/hda2 is swap, /dev/hda3 is /root and /hda4 is /home

    I thought that it had to point at the /boot i.e. hd0,0 and not the /root (hd0,2) ??

    Or have I got this the wrong way round (well has genkernel got it the wrong way round? as that's what I always use to do kernel installs/upgrades)??

    regards

    John

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    Code Listing 8: Installing GRUB in the MBR

    grub> root (hd0,0) (Specify where your /boot partition resides)
    grub> setup (hd0) (Install GRUB in the MBR)
    grub> quit (Exit the GRUB shell)
    is what it says in the gentoo install guide for 2005.0 and hd0,0 is where the /boot partition is.

    I'm really confused now

    regards

    John

  5. #5
    Linux User Stefann's Avatar
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    GRUB loads all of its data off of the /boot partition before it even displays the menu. That's why if you move it, or delete it grub won't load your system. You need to point the hd(0,0) entries to hd(0,3), as that is where they are looking for the *root* partition. It was clearly stated in the error message. It looks for the root device to mount on this partition and when it reads hd(0,0) it finds that it is '/boot' instead of '/'. Change these and you should be good.
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    Quote Originally Posted by Stefann
    GRUB loads all of its data off of the /boot partition before it even displays the menu. That's why if you move it, or delete it grub won't load your system. You need to point the hd(0,0) entries to hd(0,3), as that is where they are looking for the *root* partition. It was clearly stated in the error message. It looks for the root device to mount on this partition and when it reads hd(0,0) it finds that it is '/boot' instead of '/'. Change these and you should be good.
    hd(0,3)???

    Just thinking Stefann, if my /root is /dev/hda3, then surely it should be hd(0,2)??

    I'll have to wait a while to test it because I've been "meddling" and added the USE flags that I should have put in before I did my post-install "emerge sync" and with the emerge -uDN world, it's decided to emerge about 150 packages

    I'll post back when I've given it a try. Thankyou for the assistance so far.

    regards

    John

  7. #7
    Linux User Stefann's Avatar
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    yeah you are right, it would be (0,2) sorry 'bout that, forgot that they start at 0 lol
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    Try this: when Grub comes up, hit "c" to get the Grub command line. Then do: 'root (hd <tab>' so Grub will tell you what dirves it sees, and then, assuming it sees hd0, do: 'root (hd0, <tab>' so Grub will tell you what partitions it sees.

    Quote Originally Posted by bigjohn
    the partitions are /dev/hda1 which is /boot, /dev/hda2 is swap, /dev/hda3 is /root and /hda4 is /home
    Where you say "/dev/hda3 is /root" you really mean "dev/hda3 is /", right? It's really unfortunate that Grub calls the boot device (/boot) "root", we pronounce the root device ( / ) "root" and under that is the home directory of the root user "/root". Too many roots.

    Stefann is not correct in suggesting that your "real_root" should be the first partition of your boot device. The boot partition only needs to hold the grub.conf and the kernel and initrd* and that is unrelated to where the root ( / ) partition is. I have an FC3 on my hde5 that I boot from my hdc1 with no problems. bigjohn, the question is where is your root ( / ) partition: hda3 or other and then make sure Grub agrees. What type of filesystem did you format your root ( / ) partition for?

    *edit:
    The boot partition also must hold Grub stages 1.5 and 2. Note that stage 1.5 is filesystem-specific: that is, it must be for the filesystem type that the root ( / ) partition is formatted as. And maybe this is the problem here. Look in /boot/grub/ to see the various stage 1.5 files available.
    /IMHO
    //got nothin'
    ///this use to look better

  9. #9
    Just Joined! bigjohn's Avatar
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    Well I did this
    GNU GRUB version 0.96 (640K lower / 3072K upper memory)

    [ Minimal BASH-like line editing is supported. For the first word, TAB
    lists possible command completions. Anywhere else TAB lists the possible
    completions of a device/filename. ]

    grub> root (hd0,
    Possible partitions are:
    Partition num: 0, Filesystem type is ext2fs, partition type 0x83
    Partition num: 1, Filesystem type unknown, partition type 0x82
    Partition num: 2, Filesystem type is ext2fs, partition type 0x83
    Partition num: 3, Filesystem type is ext2fs, partition type 0x83

    grub> root (hd0,
    but then decided "bollocks to it". For the moment.

    I'm still trying to find out what I need to do so that I get a proper grub startup screen.

    As I only get a black screen with single blinking cursor top left, if I hit return, I get just about unreadable text for about a second or two, then the system starts to boot.

    I'm starting to suspect that this might be part of the same problem, and at the moment, the grub.conf looks like this
    default 0
    timeout 30
    splashimage=(hd0,0) /grub/splash.xpm.gz

    title=Gentoo Linux 2.6.11-r3
    root (hd0,0)
    kernel /kernel-2.6.11-gentoo-r3 root=/dev/ram0 init=/linuxrc ramdisk=8192 real_root=/dev/hda3 udev vga=0x317 splash=verbose
    initrd /initrd-2.6.11-gentoo-r3
    Plus, if the other error as detailed above is present, then I won't be able to upgrade my kernel will I???

    Any ideas please ???

    regards

    John

  10. #10
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    Since this morning, I've re emerged the kernel version. No luck.

    I've also tried dumping grub and installing lilo, but apart from getting a "proper" lilo boot options screen, I'm still getting the same error i.e. the:

    >>Block device /dev/hda3 is not a valid root device
    >>The root block device is unspecified or not detected

    Please specify a device to boot, or "Shell" for a shell.....
    error. As it appears when trying to boot the system with both grub and lilo, I think it's not the bootloader.

    It's got to be something to do with either the kernel or genkernel (and this time, even though I really don't know enough about the hardware to try doing menuconfig, I did
    Code:
    genkernel --menuconfig udev all
    exactly as it says in the kernel upgrade guide - I did go through all the options in menuconfig too see if I could see anything obvious, but as I say, I don't know enough about the hardware to trust myself to select any, but the most obvious amongst the multitude of options).

    maybe someone could advise me on what I need to do, or where to look next to try and sort this out???

    regards

    John

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