Qt Development Frameworks (formerly known as Qt Software, Trolltech and as Quasar Technologies) is an Oslo, Norway-based software company best known for its Qt toolkit and application framework. Qt Development Frameworks is a wholly owned subsidiary of Nokia Corporation. Trolltech introduced Qtopia which is based on Qt. Qtopia is an application platform for Linux-based devices such as mobile phones, portable media players, and home media. It is also used in many non-consumer products such as medical instruments and industrial devices.