Increasingly popular approaches such as virtualization, cloud computing, and application development frameworks are changing the importance of the traditional operating system. Virtualization lets a single server host slices of multiple operating systems, each of which can run different applications within virtual machines. This makes the installation of any single full-featured OS instance a choice rather than a necessity. Cloud computing features applications that run on servers spread across the Internet. Cloud providers push these applications to users' browsers. Users of cloud based software thus don't need an OS to do more than run the browser. Developers are increasingly using frameworks that enable the faster building of applications that work with multiple OSs, again making the use of a specific operating system less important. The just enough operating system (JeOS, pronounced "juice") movement focuses on packaging an application with only the parts of an OS necessary for it to work. Over time, these developments could affect what constitutes an operating system, what its roles and responsibilities will be, and how it will be installed and used.