For users who would like to use Linux and Windows there is an alternative to owning two machines or using emulation.  This alternative is to dual boot their computer.  To dual boot means that two operating systems are installed on a single computer and the user selects the one he wishes to use on startup.  Each operating system requires its own hard drive partition.  This can be done by giving each operating system a partition on the same hard drive.  A much easier way to do this is to give each operating system its own hard drive.  The operating system that is run is selected by means of a boot loader.  A boot loader is a program that allows the user to select which operating system is to be run.  Windows XP comes with a boot loader.  There is also a free GNU boot loader call Lilo which is more robust and gives the user more options.  Dual booting is cheaper than purchasing a second PC to run the other operating system, nothing needs to be purchased (except the operating system in the case of Windows).  Dual booting is better than emulation because the emulated operating system runs slowly because it all of its hardware requests must go through the host operating system.  Dual booting is limited because it only allows one operating system at a time to be run, whereas a second pc and emulation allow the user to use both operating systems simultaneously.