Dual-boot Ubuntu 12.04 and Windows 7 on a computer with 2 hard drives

This is the second article on dual-booting Ubuntu Desktop 12.04 with Windows 7. But while the first one, how to dual-boot Ubuntu 12.04 and Windows 7, showed how to do it on a computer with a single hard drive, this one gives a step-by-step guide on how to do it on a computer with two hard drives.

If you have a computer with two hard drives or if you can afford to add a second drive to your computer, you give yourself the best hardware configuration for dual-booting, as it avoids the single point of failure that dual-booting on a single hard drive presents. And if you have a computer with UEFI firmware, see Dual-boot Windows 7 and Ubuntu 12.04 on a PC with UEFI board, SSD and HDD.

The operating assumption here is that Windows 7 is installed on /dev/sda, the first hard drive recognized by the system, and Ubuntu 12.04 will be installed on /dev/sdb, the second hard drive. And rather than use Ubuntu’s automated installation mode, all its partitions will be created manually. So aside from showing how to dual-boot Ubuntu 12.04 and Windows 7 on a computer with 2 hard drives, this article serves the secondary purpose of showing how to create partitions manually for installing Ubuntu 12.04 on any computer.

By default, the Ubuntu 12.04 is installed on two partitions – the root partition and Swap. For this tutorial, it will be installed on four – the boot partition, root partition, home partition, and Swap. The boot partition is where all boot-related file and folders are located. Root holds all installed programs, while home is the place for all user-generated data, that is, where your home folder and that of other users on the system are located. Swap is disk space that the computer may use as virtual memory. Creating a separate partition for home makes it relatively easy to upgrade the system without messing with your data.

After the installation has completed, the computer will always boot into Windows, since it is installed on the first hard drive. At that stage, you have two options, if you want to be able to boot into Ubuntu: Change the default boot disk to /dev/sdb in the BIOS, or add an entry for Ubuntu in Windows 7′s boot menu. Because Ubuntu’s installer automatically adds an entry for Windows 7 in GRUB’s boot menu, using the first method requires very little effort; no additional software installation is required. The second method involves installing a special program on Windows 7. From experience, the second method is not necessary, so the recommendation is to use the first method.

Ok, enough introduction. On to the task at hand. If you have not done so already, download an installation image of Ubuntu Desktop 12.04 for your platform from here. Transfer it to a suitable media, then boot the computer from it.

If you are new to Linux and are not familiar with disk partitioning in Linux, read guide to disks and disks partitions in Linux before diving into this. Also, reading tips for dual-booting Windows and Linux is highly recommended.

During bootup, you may opt to boot into a Live desktop environment or start the installation process without making a customary stop at the Live environment. If you boot into the Live desktop, start the installer by clicking on the Install Ubuntu 12.04 LTS icon on the desktop.

However you start the installer, click through the first steps until you get to the disk detection step. That step is shown in the image below. Since you are going to be creating partitions manually, select Something else, then click Continue. Keep in mind that even if you do not want to create partitions manually, it is better to select the same option as indicated here. That is the easiest way of ensuring that the installer will not overwrite Windows 7, which will destroy your data. The assumption here is that sdb will be used just for Ubuntu 12.04, and that there are no valuable data on it.

Selecting Something else and clicking Continue in the previous step should open the Advanced Partitioning Tool. You should see the disks and partitions connected to the computer. At the top of the list is sda, where Windows 7 is installed. You do not want to mess with that one. Any action you take here MUST be on sdb, the target disk for Ubuntu 12.04. If there are existing partitions on it, as in this example, delete them. You do that by selecting each partition and clicking Delete. Again, be sure that you are not messing with any partition under sda.

After all the partitions (under sdb) have been deleted, select the free space and click Add.