[SOLVED] device for bootloader installation

[beirapadua]

i plan to install linuxmint 14 here: /dev/sda1
which is recommended?
installing bootloader in /dev/sda1 or /dev/sda ? what difference does it make??
on my first try i install the bootloader in /dev/sda1 and got a problem on the next reboot.
As soon as the computer reboots: 'file not found: grub rescue >' error is displayed.
please help and advise. thank you

[viking777]

You have to install one version of grub to /dev/sda or you will never get anything to boot - ever! If mint is the only distro you have on the machine then it has to go on /dev/sda. If you have another boot loader already on /dev/sda (not counting windows) then you could install to the partition, not otherwise.

[beirapadua]

thanks alot viking777.
yes linuxmint is my only distro.
say, out of curiousity, how different is /dev/sda from others like /dev/sda1 etc

[viking777]

say, out of curiousity, how different is /dev/sda from others like /dev/sda1 etc

/dev/sda is an entire hard disk. /dev/sda1 is a partition, a sub division of an entire disk. Partitions are what enable you to separate out operating systems or maybe personal information so that in the event that you have a problem with one part of a disk it doesn't affect other parts. It is a bit like a desk with different drawers in it. Partitions are very useful, but to extend the desk analogy a bit, there is no point in putting your desk lamp in a draw because you wont see any light from it, it has to go on top of the desk. Bootloaders are the same, at least one of them has to live on top of the desk or otherwise your bios can't find it and can't boot from it.

If you ever install another linux distro you can install its bootloader to a partition (keep it in a drawer in our analogy) because the bootloader on the disk (the top of the desk) is clever enough to look into the partitions (drawers) to find it, but your bios is not clever enough to do that, it is a tiny little chip and is only programmed to look in one place.

You can also put bootloaders onto external disks, even floppies, but let's not complicate things too much.

[caf4926]

https://dl.dropbox.com/u/10573557/Mint_ ... loader.png

[beirapadua]

thank you guys.. very informative for a newbie like me

[srs5694]

You have to install one version of grub to /dev/sda or you will never get anything to boot - ever!

This isn't entirely true. In fact, you seem to be aware of at least one exception....

If mint is the only distro you have on the machine then it has to go on /dev/sda. If you have another boot loader already on /dev/sda (not counting windows) then you could install to the partition, not otherwise.

In the BIOS boot scheme, one boot loader sometimes chain loads to another, so as you say, a boot loader in /dev/sda can chain load to a boot loader in /dev/sda1 (or elsewhere). In fact, contrary to what you wrote, Microsoft's boot loader can do this job -- you just need to adjust the boot flags on your disk so that the partition that holds GRUB is marked as bootable and the Windows partition is not marked as bootable. This type of configuration is uncommon with GRUB 2, though; it's usually installed to the MBR (typically /dev/sda). This is quite different from saying that it must be installed to the MBR.

Another exception is EFI-based computers, which don't use boot code in the MBR at all; they use files stored on the EFI System Partition (ESP). Although most existing computers don't support EFI, most new computers do, so it's important to acknowledge their existence and determine if somebody asking a question has such a system. To that end: beirapadua, how old is your computer? Did it come with Windows pre-installed, and if so, what version? Please post the output of "sudo parted /dev/sda print" from a Linux emergency disc. This information will help us determine whether you need to install a BIOS boot loader or an EFI boot loader.

[beirapadua]

thanks alot

[viking777]

As always what you say is unimpeachable srs, but you have to read between the lines a bit. The OP has been offered a choice of installing his boot loader in /dev/sda or /dev/sda1. Is there ever a case where a whole disk (/dev/sda) can be an ESP? I personally doubt it. Not only that, but if this were a Uefi system and /dev/sda1 was his ESP then when he installed his bootloader there the system should have booted anyway- and it didn't.

[srs5694]

As always what you say is unimpeachable srs, but you have to read between the lines a bit. The OP has been offered a choice of installing his boot loader in /dev/sda or /dev/sda1. Is there ever a case where a whole disk (/dev/sda) can be an ESP? I personally doubt it. Not only that, but if this were a Uefi system and /dev/sda1 was his ESP then when he installed his bootloader there the system should have booted anyway- and it didn't.

I've seen so many buggy installers that I can't keep track of them all. Some of them have continued to offer the sda/sda1 type distinction even for EFI installations to which that distinction is completely irrelevant. Making assumptions in the face of such bugs is a road to wasted effort.

[beirapadua]

sori srs,, i didnt read the whole line but this is the output of what u asked for:
Model: ATA ST500LM012 HN-M5 (scsi)
Disk /dev/sda: 500GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos

Number Start End Size Type File system Flags
1 1049kB 25.6GB 25.6GB primary ext4 boot
2 25.6GB 230GB 205GB primary ext4