Ubuntu Dual Boot Tutorial

Overview

GRUB Bootloader

The following information pulled from the GNU GRUB Manual (link):

Briefly, a boot loader is the first software program that runs when a computer starts. It is responsible for loading and transferring control to an operating system kernel software (such as Linux or GNU Mach). The kernel, in turn, initializes the rest of the operating system (e.g. a GNU system).

GNU GRUB is a very powerful boot loader, which can load a wide variety of free operating systems, as well as proprietary operating systems with chain-loading1. GRUB is designed to address the complexity of booting a personal computer; both the program and this manual are tightly bound to that computer platform, although porting to other platforms may be addressed in the future.

One of the important features in GRUB is flexibility; GRUB understands filesystems and kernel executable formats, so you can load an arbitrary operating system the way you like, without recording the physical position of your kernel on the disk. Thus you can load the kernel just by specifying its file name and the drive and partition where the kernel resides.

When booting with GRUB, you can use either a command-line interface (see Command-line interface), or a menu interface (see Menu interface). Using the command-line interface, you type the drive specification and file name of the kernel manually. In the menu interface, you just select an OS using the arrow keys. The menu is based on a configuration file which you prepare beforehand (see Configuration). While in the menu, you can switch to the command-line mode, and vice-versa. You can even edit menu entries before using them.

Configuring GRUB Settings

How To Geek has a useful page describing various ways to interact with and improve GRUB. Follow the link (link).

If all you want to do is make your GRUB auto-boot to Windows or turn off the auto-select process, follow these steps (referenced from the above HowToGeek link):

1. Boot into Ubuntu and open a new Terminal.
2. Navigate to your /etc/default directory by executing the command:
   cd /etc/default
3. Using your favorite text editor (or gedit as used in this example), open the grub file with admin privileges:
   sudo gedit grub
4. To turn off auto-selection, change the number in the following line to -1:
   GRUB_TIMEOUT=-1
5. To change your default boot OS, change the number in the following line to the item in the GRUB list that you want to boot by default. You may need to restart your computer to figure out which option that is:
   GRUB_DEFAULT=0
6. Once you've made your changes, save the file and run the command: sudo update-grub