LDJ95 wrote:I've been trying to install Ubuntu 12.04 to my portable external HDD (USB-powered), and have run in to a few issues. The drive is ~931GB, and I've separated it into five partitions: a 750GB storage partition & a 60GB backup partition, a 110GB Ubuntu partition, a 10GB swap partition, and there's also about 1.5GB of unused, unformatted space.
Actually, that's four partitions. Your unused space is, by definition, unpartitioned. If, as seems likely, you're using the older Master Boot Record (MBR)
partitioning system, this layout means you won't be able to use that unused space in the future without jumping through some extra hoops. That's unrelated to your current problem, though, so I wouldn't worry about it just yet. Keep it in mind and post back (or start a new thread) once you've fixed your current problem, though.
I went about the installation from a LiveCD, and I seemingly successfully installed Ubuntu to the external HDD. Under the 'Something Else' option during the installation, I made sure to select my external HDD as the location to install GRUB (/dev/sdb),
After, I tried booting off the external HDD, and was taken to the GRUB rescue menu:
error: unknown filesystem.
grub rescue > _
So, I booted back into my LiveCD and searched around for a bit, and on the way noticed that GRUB had been installed to /dev/sdb3 (my Ubuntu partition), under the folder /boot/grub. From what I understand, this is because GRUB automatically installs where ever the OS does? Maybe not.
GRUB doesn't install in just one place; it puts bits of itself all over the place, including code in the first sector of the hard disk, code in various other unpartitioned sectors of the hard disk, and files in one or more Linux partitions. The location specified during OS installation is for low-level boot code. That part of the process probably completed successfully, but I can't be 100% positive of that from the information you've provided. To gather more data, I recommend you download the Boot Info Script
and run it from a Linux emergency disc (such as the Mint installer in its "try before installing" mode). Be sure to run the script with your external disk plugged in. This script will produce a file called RESULTS.txt. Post it here, either as an attachment or between code tags. That will provide the information we need to provide a diagnosis that's not based on guesswork.
The only thing I can possibly think of is that the partitions need to be at the 'front' of the drive, if that even makes any sense?
What you're saying makes sense, in that I understand what you mean, but it's probably not the cause of the problem (see below)....
Partitioning is faulty. The bootable partition is too far from HDD´s beginning so that why grub rescue> comes ..
All BIOSes have limits on how much disk space they can address. For a modern BIOS (that is, anything sold new in the last few years), the limit is 2 TiB or higher. LDJ95's disk is half that size, so a BIOS limit is unlikely to be the culprit unless the computer is an older model. IIRC, the latest limit that was smaller than 2 TiB was something on the order of 128 GiB, and that limit was raised several years ago. I'd guess 2005-2007 as the latest for that limit, but I could be off. Certainly, information on the age of the computer is relevant to get a better handle on whether this possibility is worth exploring further.
LDJ95 wrote:"Partitions closer to the outside of the hard drive disk, i.e. at the top of your partition table and to the left in the GParted graphic, are faster than partitions on the inside of the hard drive, or closer to the bottom of the partition table."
This quote is referring to disk performance (speed). It's irrelevant to your problem of GRUB failing.