If you install more than one operating system on a computer, and install Linux last, you normally get a Grub menu, where you select which operating system you want to use each time you turn on the computer.
During installation, most Linux distributions detect other operating systems, and automatically include them in the Grub menu.
A few operating systems, which are different from the common ones, are not automatically included in the Grub menu, but can be added.
While most Linux distributions set up Grub automatically, with a few you need to set it up manually.
A few Linux distributions use programs other than Grub for a start menu.
To install more than one operating system on a computer, also see Partitioning.
Edit the Grub Menu
To edit the Grub menu, open /boot/grub/menu.lst with a Root Text Editor.
If you don't select an operating system when you start the computer, Grub will automatically start the first one on the list.
You will see "timeout 5," or another number. This tells Grub how many seconds to wait before starting that operating system. You may change that number to the number of seconds you want Grub to wait.
Any lines starting with "#" are comments.
If you install Linux last, it will automatically detect Windows, and include it in the Grub menu.
If you want to add Windows to Grub manually, add:
Change (hd0,0) to whatever partition Windows is in.
Two Versions of Windows on the Same Computer
Windows is designed to be the only operating system on a computer. If you install two version of Windows on the same computer, Grub needs to hide the other version when the computer starts. For two versions of Windows on the same computer use:
Change Windows versions and partition numbers as appropriate.
The easiest way to find out the Grub commands for Linux operating systems is to install Linux last, and they will be automatically included.
If you use one of the few Linux distributions which do not automatically set up Grub, you can normally find the Grub commands for them on the internet.
For Slax Grub commands, see: Install Slax.
For Tiny Core Grub commands, see: Install Tiny Core.
Drives and Partitions
When using Windows, you only see Windows partitions. You cannot see Linux partitions.
The first partition is called "C:"
The second partition is called "D:"
The third partition is called "E:"
and so on.
When using Windows, there is nothing to indicate whether they are different hard drives, different partitions on the same hard drive, or a combination of both.
If you want this information, you can run GParted. You can see how the partitions are set up without making any changes.
When using Linux, the first letter designates an IDE or SATA hard drive ("h" for IDE and "s" for SATA), the second letter is always "d," the third letter designates the hard drive number, starting with "a," and the number at the end designates the partition, starting with "1."
When referring to the entire drive, there won't be a number.
The first drive is called "hda" or "sda"
The second drive is called "hdb" or "sdb"
The third drive is called "hdc" or "sdc"
and so on.
The first partition on the first hard drive is called "hda1" or "sda1"
The second partition on the first hard drive is called "hda2" or "sda2"
The third partition on the first hard drive is called "hda3" or "sda3"
The first partition on the second hard drive is called "hdb1" or "sdb1"
The second partition on the second hard drive is called "hdb2" or "sdb2"
and so on.
When using linux, you can see all partitions, including Windows partitions.
When referring to the entire drive, there will be one number, starting with "0."
The first drive is called "(hd0)"
The second drive is called "(hd1)"
The third drive is called "(hd2)"
and so on.
When referring to partitions, the first number designates the drive, starting with "0," and the second number designates the partition, starting with "0."
The first partition on the first drive is called "(hd0,0)"
The second partition on the first drive is called "(hd0,1)"
The third partition on the first drive is called "(hd0,2)"
The first partition on the second drive is called "(hd1,0)"
The second partition on the second drive is called "(hd1,1)"
and so on.
Notice, Grub starts with "0," so in Grub the number is always one less than the actual number. If you don't get it right, it won't work.
© Copyright Guy Shipard 2008 - 2009