Dual-Boot Windows and Ubuntu

By Stephen Bucaro

Ubuntu is available as a "live" CD, which means that you can use it directly from the CD without installing it. But running an operating system from a CD is slow, to see what Ubuntu can do running at full speed, you need to install it to your hard disk.

The ideal situation would be to install Ubuntu on it's own separate hard disk, but most people don't have two hard drives in their computer, and most people are not prepared to give up Windows. Therefore they have to install Ubuntu along-side Windows on the same hard disk in a dual-boot configuration.

Configuring a dual-boot system involves partitioning your hard disk to make space for Ubuntu. When your computer first starts, it reads information on the first sector of the hard drive which tells it where to find the "boot loader". The boot loader is a file with information about the installed operating systems and how to start them.

The boot loader for Windows is a file named "boot.ini". The boot loader for a Linux system (like Ubuntu) is GRUB (Grand Unified Boot Loader). When you install Ubuntu in a dual-boot system, it redirects the system to use GRUB. When you first start your system, GRUB presents a list of options, including starting Ubuntu or starting Windows. So you'll still be able to use your Windows operating system.

To install Ubuntu, start it with the live CD. To use the live CD, your computer's BIOS must be configured to boot from the CD drive. It's probably already configured that way, but if not, when your computer first starts watch for a message telling you which key to press to access the BIOS setup. Most computers use the F2, F1, Esc, or Del key.

When the BIOS setup screen appears, select the Boot option, configure the CD drive in the boot order before the Hard Disk drive, then follow the instructions to save your change and exit. This change will not effect the normal operation of your computer except for a slight delay when it starts to check the drive for a bootable CD.

Because Ubuntu live CD creates it’s file system in RAM, it requires a system with a least 512 MB of RAM. Some sources claim the minimum is 256 MB, but I haven’t had any luck getting Ubuntu live CD to boot on systems with less than 512 MB of RAM.

Installing Ubuntu as a dual-boot system involves partitioning your hard disk to make space for Ubuntu. If you make a mistake in the partitioning process, you could lose your Windows operating system. I'm going to explain the partitioning process in complete detail, so the chances of making a mistake are minimal, but you should still make a complete back up just in case.

You'll need at least 10 GB of free space for Ubuntu on your hard disk. You should also leave at least 10 GB of free space for Windows after you install Ubuntu. So if you don't have at least 20 GB of free space on your hard disk, you should remove any unnecessary programs and files first.

Then run Windows Disk Cleanup utility to get rid of any other unnecessary files. You should also run Windows Defragment utility to move the data on your hard disk to consecutive allocation units, which will make it easier to partition the disk.