DualBoot Windows-Fedora (Fed. on external USB HDD)

palwin

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Jun 17, 2010
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Hi,
looking for help with the problem:
I have Vista installed originally on my PC. No troubles with that. Decided to work with Linux on my project, and ideally for me is not to keep both the OS on the same disc. So I installed Fedora 13 on external USB HDD 500GB. All good so far. Installation finished, doing the reboot and there all the troubles come. I can not boot Fedora from the external.
I can see the external in BIOS (under its original name) as HDD. I can set up the boot order so the first to boot is "Removable dev." No luck booting, just a blank screen.
I`ve tried several configurations installing Fedora, just in case (usually I follow guides on the net, but so often it`s incomplete, missing many informations on dependencies and so... and I am not an expert). Grub installed to the first boot sector, installed to the MBR... no luck booting. When I see the output from fdisk -l I can see there is bootable partition on the external (marked as 83 Linux, it`s 3rd one, the first two are NTFS - just for some storage, no OS there).
I`ve tried using some software as well, like EasyBCD (even the beta version), or GAG, both configured all the possible ways. Usually I can get the boot menu (GRUB) after starting up PC with the menu.lst configured, but can`t boot into Fedora. Mostly it says something like file not found..., or partition not found... depends on the actual configuration at the time as I play around. Maybe important thing is that in the menu.lst there is the HDD marked as hd0,2 after installation and I can`t change that (at least don`t know how since I can`t boot Fedora).
It took me about two weeks already playing around, but I`m still not able to boot Fedora from the external.
I might be missing something somewhere, but can`t help myself any more.
Hope to get some help here. Any ideas?
 

DJRWolf

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I've always just selected the external drive in the boot menu. Just be careful as I have screwed up the Windows install when installing linux. I have taken to the habit of disconnecting the internal drive when I install linux on an external to make sure nothing gets overwritten.
 

palwin

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Jun 17, 2010
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Thanks for sharing your experience, however, while trying to get it working, I`ve installed Linux several times so far configured several ways and fortunately there`s been no troubles screwing up Windows, I got lucky so far at least.

It doesn`t work so easy in my case. Fedora not booting yet. Just thinking if it may cause booting troubles having NTFS partitions to be the first two partitions of the external. So I`m moving partitions now and will install Fedora again, but now to the very first partition of the disc. Will see...
However, I do think, that the problem comes with installation of the GRUB. In menu.lst I can see the external booting partition is marked as hd0,2. Not sure, but it`s like not considering the internal drive to be installed there as well which is the first one obviously thus hd0. The external should be marked as hd1, shouldn`t it? Is there any way I can edit the menu.lst to change it with access to terminal through Live CD?
I`d appreciate if someone could reply, or better, post the steps to be taken.
Thanks.
 
Your trouble here is that you are specifying the external drive as being internal. USB devices are not listed as hdX, hd is for devices on the internal bus so you will never see your drive this way. Have a check but you will likely find your drive is actually under the sda device lists.

Yes, you can edit menu.lst from the terminal although you will likely have to do this as root (sudo nano menu.lst)
 

palwin

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I`m no expert, but both is right, depending when, where and how it`s used, like sdb3 = hd1,2, sda1 = hd0,0 ... with no difference internal/external. Am I wrong?

I have one internal HDD, one external HDD.
In the device list (fdisk -l) there is the internal HDD marked sda, the external HDD marked sdb, the boot partition is sdb3 - second HDD, third partition.
But in GRUB menu.lst it`s configured to be hd0,2 - first HDD, third partition. And that`s the problem probably.

Thanks for letting me know how to edit the file, I`ll try to change it to hd1,2 as it should be perhaps.
 

palwin

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Jun 17, 2010
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It`s solved, finally. However, I haven`t taken the chance to change the configuration of menu.lst.
It seemed to me that the main problem was in the mbr of the disc. Probably it can be placed just to the first sector of the HDD, so there has to be space available in the very beginning of the disc. Since there was NTFS partition with no OS as the first partition, the external HDD was without mbr being present actually, and thus placing a boot sector anywhere was pointless. There might be a better explanation, I`m just a beginner.
So, I resized and moved the first NTFS partition and made a free space before, so the first became an unallocated space on the HDD. Into that I installed Fedora, configured the /boot to be installed to the very first sector of the HDD, GRUB installed to the mbr in my case (since it`s the first and the only one OS on that HDD), and it works just fine. Now I can boot Fedora two ways without troubles. First when I set up BIOS to boot the external first, it boots straight away. Or I can set up BIOS to boot the internal first, and during BIOS start up press F8 (in my case) to choose where to boot from, select the external from the list and it works now.
All that was not possible before without the mbr being present and installed in the first sector of the HDD.
I don`t want to go into any more details so not to confuse anybody with a bit different environment, it can make a difference possibly. So anybody with a proper technical explanation/details welcome to post it here.