Any system offering the user the choice of two operation systems (OSes) under which to start a computer. A dual boot system allows the user to run programs for both operating systems on a single computer (though not simultaneously). The term "multiple boot" or "multiboot" extends the idea to more than two OSes. The OSes are generally unaware of each other' s existence. They are installed on separate hard diskpartitions or on separate disks. They may be able to access each other' s files, possibly via some extra driver software if they use different file systems. The OSes need not be completely different - they might be different versions of Microsoft Windows (e.g. Windows XP and Windows NT) or Linux (e.g. Debian and Fedora). A dual boot system differs from an emulator such as vmware, which runs one or more OSes "on top" of the primary OS, using its resources. (2005-02-01)
