Dual/Multi Boot
The most common method of doing multiple operating systems
Boots off a Master Boot Record
Then accesses individual partition boot records each of which can run a totally independent operating system
Can run single or multiple operating sytems, individually(by default) or simultaneously (with virtual operating system support)
Is supported for all PC-based operating systems as well as free managers on other processor versions of Linux
Requires a boot manager such as the Linux lilo, System Commander, Boot Magic, NT Boot manager, etc.