Android (operating system) and rival Linux mobile operating systems that were in development. These established players were skeptical: Nokia was quoted as saying "we don't see this as a threat," and a member of Microsoft's Windows Mobile team stated "I don't understand the impact that they are going to have." Since then Android has grown to become the most widely used smartphone operating system and "one of the fastest mobile experiences available". Reviewers have highlighted the open-source nature of the operating system as one of its defining strengths, allowing companies such as Nokia (Nokia X family), Amazon (Kindle Fire), Barnes & Noble (Nook),
Network operating system Network operating system The term network operating system is used to refer to two rather different concepts: Network operating systems can be embedded in a router or hardware firewall that operates the functions in the network layer (layer 3)."" Early microcomputer operating systems such as CP/M, DOS and classic Mac OS were designed for one user on one computer. As local area network technology became available, two general approaches to handle sharing arose. In a peer-to-peer network operating system users are allowed to share resources and files located on their computers and access shared resources from others. This system is