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Old December 15, 2010, 07:52 AM
Join Date: Dec 2010
Posts: 7
Default dual boot need resolved to my satisfaction

This has been resolved and it was far easier than I expected. A bootloader did not need to be installed because it was already present. It turns out that when you install Ubuntu 10.10 without the slightest hint that another OS might need accommodation, Ubuntu still goes ahead and installs and invokes grub2 the bootloader. So in my case, my Windows hard disk was removed from the machine, a new blank hard disk was installed and Ubuntu was instructed to use the entire space so there was no hint of a need to dual boot. Fortunately, Ubuntu will still use a bootloader when there is no hint of Windows or any other operating system present.

When Ubuntu boots via grub2 it should wait 10 seconds to let you select from a normal Linux or a recovery mode Linux. Earlier, I had not noticed this since I run dual portrait mode monitors and often fail to read what passes in front of me in landscape mode. Since grub2 is executed early, you will still be in landscape mode. It's easy to change the timeout (default 10 seconds) so you get paused on the grub2 screen so it would be impossible to not notice.

I proceeded to install my Windows hard disk in the (now) Ubuntu machine and the BIOS detected both disks. Fortunately, by chance the Ubuntu disk had priority (in BIOS) when booting so we end up in grub2. The good thing about Ubuntu's grub2 is that there is a script to detect other operating systems and although my alternate operating system was on a different physical drive, it was detected and added to the landscape mode boot menu. Other Linux flavours might require you to write and install a grub2 script for Windows if they don't have a generic OS-detection script.

I'm not sure if the BIOS master/slave settings might need reversing in some cases, but if so, then what I describe here has a 50% chance of working on the first try. According to some, the master/slave concept does not apply to SATA drives and both of mine are SATA. Regardless, the BIOS lets me reverse the priority of the two hard disks which happen to both be bootable. Reversing them, BIOS boots the Windows disk and there seems to be no obvious intermediate stage, that might look like a bootloader, before the full Windows desktop appears. You are better off to make the Linux disk take priority in the BIOS setting so that you get to see an intermediate stage: grub2.

Bottom line: someone suggested just using BIOS to pick your OS and if your systems are on separate bootable physical disks, as mine are, then that seems feasible. If not, then making the Linux disk take priority in BIOS means you get a chance to choose via grub2 (even if this need was not previously anticipated nor prepared for). There was also the suggestion that it is always better to install Windows (and presumably partition the single disk) before installing Linux if you need to have a dual boot system. My preference is to spend $50 to buy a new disk for your second bootable system in which case the install order is not relevant. Then use BIOS or grub2, which seem equally effective, to switch between systems.

Last edited by broiyan; December 15, 2010 at 08:58 AM.
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  #22 (permalink)  
Old December 15, 2010, 08:58 AM
ipaine's Avatar
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By far the easiest way to set up a dual boot is to go windows 7 install then ubuntu install, but they can be installed in any order. If done properly you will be prompted everytime you reboot with the Grub2 menu. In that menu you will see options for Ubuntu (and some rescue options) and Windows 7. Then you just select the one you want. It does not matter if the OSes are on different drives.

If I understand your last post once you added the windows disk back into the system you now see an option in the grub menu to boot to Ubuntu and an option to boot to windows. That is what you want. Your windows install will not "see" the Ubuntu disk (well it will show in disk management, but will not get a drive letter) and your windows drive will be seen in Ubuntu but should be easy not to do anything with it.

Going into the BIOS to switch what disk is first to boot, is just way to involved and takes too much time. I just see no reason to do it like that.
"Nothing sucks more than that moment during an argument when you realize you're wrong."

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  #23 (permalink)  
Old December 16, 2010, 12:58 AM
Join Date: Dec 2010
Posts: 7
Default one problem with using BIOS to switch operating systems

I did notice one problem with using the BIOS to switch operating systems. The BIOS identifies the hard disks by make and model number. If your disks are all the same make, then you can't tell which is which. I would have to agree grub2 as implemented in Ubuntu is more convenient and practical.
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