Have matched pair of SATA II 3.0 250 GB hard drives. Installed XP on drive sda. Then installed Core 6 on sdb. Installation said installing boot loader. But have no idea where it is. Boots only to XP, no GRUB Screen, no matter what I do. I take it that GRUB must go on the first sector of the first active drive controller a drive is attached to? Must /boot also be located on the same drive as GRUB? In the above case what happened to GRUB? If I F11 to sdb still does not boot. Same if I change first boot drive in BIOS. Even tried disabling the sda drive controller. When I force to look at sdb says no OS, or Bootloader found, or something like that.
Thanks
Terry

It looks like the grub bootloader wasn't written to the MBR of either disk. See if you can boot up to the install disk. Press [ESC] on the grub menu and see if you can boot manually from the grub shell. For example, you might enter:
kernel (hd1,1)/boot/vmlinuz
initrd (hd1,1)/boot/initrd
boot

Use autocompletion to find the correct drive, partition, and file for the kernel and initrd file. There might be symbolic links (vmlinuz & initrd) pointing to the actual kernel and ramdisk file which you can select.

If you can boot up this way, then run grub-install to write grub to /dev/sda.

Thanks
Will try that. Up all night and have to go to work so later. Will let you know how this comes out. Looks to me like GRUB must be installed on the first PHYSICAL drive controller that a drive is connected to, no matter if you use F11 or BIOS to change the Boot order? Seems like a Bug to me that the default install did apparently not install, or update, GRUB at all when I did the install on the second drive?
Terry

every fedora install I've done, you get a choice of where to install grub, to the MBR (of primary hard drive) or the boot partition. Did you see this screen???

No. Using Core 6 default install. No customization or partition review. Never get that screen? When I was having this problem on two different computers (exactly the same problem) had pre fdisk and formatted a vfat partition for data to be shared between Doze and Fedora. Friend suggested removing the vfat partition and then trying the install. Did so and now it boots fine to the second drive using F11. Apparently having that vfat partition on a portion of the drive before hand causes this problem. No idea why?

That's a mystery to me, when I've installed fedora to drive b and wanted to boot from that, I've disabled drive a (pulled it's power lead) during the install proccess. That makes sure fedora installs grub to the MBR of drive b.
Then you can play with grub so it will boot doze as well, then you don't have to play around with bios, but doze will still boot from drive a if needed.

And I've never had a problem with vfat partitions already installed.

I had a very similar problem to your issue myself.

My headaches and findings can be found here.

http://www.linuxquestions.org/questi...d.php?t=500958

For some reason GRUB only 'likes' to be installed on the first HDD on the Primary IDE cable. I found that out the hard way.

If you don't want to read all the posts in that thread, my ultimate solution ended up being that I took the drive I wanted to install Linux on and put it on the Primary IDE cable as a Master. Then, I proceeded to install Fedora. I rebooted the machine and Fedora Core booted up normally. I then switched Fedora back to my secondary Master, replacing my original Primary Master (My windows HDD) to its original place.

Now, when I want to boot Fedora, I simply hit F11 and select my Secondary Master from the list, no multi booting necessary.

What I figured out was that if I put a FAT32 partition on the drive first and Formatted it using MS ahead of time then for some reason could not get the thing to boot to Fedora. Ended up creating the Fat partition but NOT formatting it ahead of time. Then had Fedora format it during the install. That works and solved my problem. I do ALWAYS disable other hard drives when installing any OS. You can simply go into BIOS and disable the drive controller of the other drive(s). Same as physically disconnecting them. SATA controllers are dual channel, ie master and slave, just like IDE. So if you have four SATA connectors 1 will be the first controller master, 2 first slave, 3 second controller master, 4 second slave. Ideal situation is to connect a pair of drives to connector 1 and the second to connector 3. That way you can enable and disable either of them from BIOS. After I got Fedora to install on the second drive re-enabled the other controller and can now use F11 to select which drive to boot from just fine.