Grub stopping with dual HD dual boot arrangement

CraigM · 12-11-2007, 05:51 PM

I have a Dell laptop with an IDE internal 60 GB HD running Win XP. I just installed Fedora 7 on an external USB 320 GB HD. During the Fedora 7 install I chose to use my internal HD for booting. However, I now have two problems:

1. If my external HD is disconnected, my computer goes through BIOS then stops with just "GRUB_" displayed.

2. If my external HD is connected the startup also stops at "GRUB_", but if I turn the computer off and quickly back on, GRUB will proceed to load stage 2, and the rest of the startup is fine.

Other things of interest that have me really confused:

If I run "fdisk -l" in Linux, it shows my HDs as labelled the reverse from what I expected:

PHP Code:


			
[root@localhost ~]# fdisk -l



Disk /dev/sda: 320.0 GB, 320072933376 bytes

255 heads, 63 sectors/track, 38913 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes



   Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *           1          13      104391   83  Linux

/dev/sda2              14       38913   312464250   8e  Linux LVM



Disk /dev/sdb: 60.0 GB, 60011642880 bytes

255 heads, 63 sectors/track, 7296 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes



   Device Boot      Start         End      Blocks   Id  System

/dev/sdb1               1           6       48163+  de  Dell Utility

/dev/sdb2   *           7        7294    58540860    7  HPFS/NTFS

Similarly for Grub:

PHP Code:


			
    GNU GRUB  version 0.97  (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.  ESC at any time exits.]



grub> find /grub/stage2

 (hd0,0)



grub> find /grub/stage1

 (hd0,0)

However, if I install the Fedora 7 distro DVD, reboot, select rescue mode, and then run Grub, I get the following:

PHP Code:


			
grub> find /grub/stage2

 (hd1,0)



grub> find /grub/stage1

 (hd1,0)

I am stumped! I thought about reinstalling Grub, but because I get different names for my HDs, I don't know how to go about it.

Thanks in advance for any divine guidance.

pljvaldez · 12-11-2007, 05:59 PM

The best thing I've done is to put a small /boot partition on the hard disk, then Grub will continue to load (that's where it's stage 2 files will be stored).

As to the swapping of drives, you might check how your bios is set. If it's set to boot from USB before booting from HD, it might be seeing the usb drive first.

PTrenholme · 12-11-2007, 06:42 PM

The reordering of your drives is controlled by your BIOS. Some BIOSs let you specify the order, others don't. On my system, I have an AMI BIOS, and the HD / USB drive order is specified in the "Drive Order" sub-section of the Boot menu, but other BIOS will do it differently. (Also, my USB drive is only shown in the menu when it's connected.)

That being said, it's fairly easy to edit /boot/grub/grub.conf to have different entries for booting with and without the USB drive connected. Here's a snippet from my GRUB configuration file that show's how I have this system set up:

Code:

title Fedora (2.6.23.1-10.fc7)
	root (hd1,0)
	kernel (hd0,1)/boot/vmlinuz-2.6.23.1-10.fc7 ro root=/dev/FC7/Base rhgb quiet
	initrd (hd0,1)/boot/initrd-2.6.23.1-10.fc7.img

title Fedora 8 (2.6.23.8-63.fc8) USB
	root (hd4,0)
	kernel (hd4,0)/vmlinuz-2.6.23.8-63.fc8 ro root=/dev/USB_Fedora/Base rhgb quiet
	initrd (hd4,0)/initrd-2.6.23.8-63.fc8.img

Note that (HD0) is my boot drive, (HD1) my Fedora 7 drive, and (HD4) my USB drive. The other drives are (HD0) Kubuntu 6.10 and Fedora 8, (HD2) Windows XP, (HD3) Windows 98, Windows NT and Windows 2000.

syg00 · 12-11-2007, 08:36 PM

I'd be betting that internal disk is P-ATA (aka IDE). I had similar issues with (internal) P-ATA and S-ATA changing names.
I just hacked the menu.lst to be "correct".

prabhat3107 · 12-12-2007, 02:13 AM

Quote:

Please Backup your data before acting upon any suggestion given

Firstly I will tell you the cause of the problem and then suggest you a possible solution.

As you have said you have a disk in the laptop(60gb) and another external USB disk (320gb). You have installed Fedora7(F7) on the external disk.

Let's first understand how Linux boot loader (GRUB) works.
Grub has 3 stages. stage1, stage 1.5(optional) and stage2. stage1, also known as primary loader, is loaded in the very first sector(512b) of a disk. This area is called MBR. It also contains the partition table.

stage1 will be loaded 1st at the time of booting. stage1 will read stage2 (optionally stage1.5). stage2 is located in the /boot partition of the linux installation. stage2 is responsible for displaying the boot menu.

therefore when you disconnect the external disk, stage one unable to load the stage2 and hence you get the error.

------------------
Suggested solution.

1. remove grub stage1 from the 1st disk(60gb).
2. Install grub in the external disk
3. When you need to boot F7 connect the external disk before starting the laptop. Press f8 or f12 to prompt for boot device menu. select the external disk.

this way you will be able to work smoothly.

CraigM · 12-12-2007, 08:56 AM

Thanks for the guidance. Yes, I have backed up all of my data. Just a couple more questions:

It makes sense that Grub Stage1 is loaded on my Win XP internal HD, but why don't I "see" it there? I doesn't show up on my C: drive when I look using Windows Explorer or the DOS "dir /A" command. Is there a way to see Grub files on my Win XP HD using Grub?

pljvaldez · 12-12-2007, 12:17 PM

The grub files on your internal HD are only in the Master Boot Record (MBR), which is something like the first 512 byte section of the disk (http://en.wikipedia.org/wiki/Master_Boot_Record), so it's not actually part of the Windows filesystem.