Purpose of Dual / Multiple Boot
Most of the time, when you purchase a computer system, it only comes with one operating system. For example, it is very common to purchase a computer that only comes with the MicroSoft operating system.
Although this may be true, your computer is designed to provide more than one operating system to work it when you start up the computer. It does not matter which operating system that the computer has, all systems will allow you to run different operating systems (depending on the available memory size of your hard disk drive).
Dual Boot means that the user is provided two operating systems to choose from upon bootup. Multiple-boot means that the user is provided with more then two operating systems to choose from upon bootup.
How it works
Generally when most Linux systems are installed, the Grub bootloader program is installed. After Linux installation and computer reboot, the Grub bootloader menu should appear offering the user with a selection of operating systems to boot. The concept is similar to the boot.ini file that NTLDR (the boot loader for Windows OS) uses to supply a menu selection for a multiple-boot system.
When the computer system starts, the computer's BIOS locates and runs the bootstrap program on the MBR (Master Boot Record). A series of programs (of Grub) are run provide the user with a selection of operating system to boot. For example, the user can select a version of Linux to load the Linux Kernel, or the user can select another operating system (like Windows) to load in the boot-loader (eg. NTLDR). This process of loading boot loaders for other non-Linux operating systems is referred to as chainloading.
Advantages of Dual / Multiple Boot
Here are some advantages of having a Dual boot or Multiple boot computer system:
- Ability to work in different Operating System Environnments
- Develop programs quickly in Linux platform
- Flexibility of running best application in best OS environment
- Ability to boot up into at least one OS in case other OS is damaged or failes to boot up