Dual-booting is a technique used in order install two working Operating Systems in your computer. Multi-booting on the other hand refers to installing two or more OS. This is pretty useful when you have certain work requirements that can't be done in one OS and it can be only done on the other. Say for example, you are using primarily Linux Operating System but in your line of work, you are required to create a sample client application in CSharp. So you need to have a computer that runs on Windows OS to code your CSharp application. Or, let's just say you want to experience or experiment on using other Operating Systems.