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),
Genera (operating system) into Genera in later releases. Symbolics improved the operating system software from the original MIT Lisp machine and expanded it. The Genera operating system was only available for Symbolics Lisp machines and the Open Genera virtual machine. Symbolics Genera has a large number of features and supported all the versions of various hardware that Symbolics built over its lifetime. Its source code is more than a million lines (the number depends on the release and what amount of software is installed). Symbolics Genera was published on magnetic tape and CD-ROM. The release of the operating system also provided most of