<P> This cost in supporting operating systems diversity can be avoided by instead writing applications against software platforms like Java or Qt . These abstractions have already borne the cost of adaptation to specific operating systems and their system libraries . </P> <P> Another approach is for operating system vendors to adopt standards . For example, POSIX and OS abstraction layers provide commonalities that reduce porting costs . </P> <Table> October 2017 worldwide webbrowsing share <Tr> <Th> Place </Th> <Th> Mobile system </Th> <Th> Desktop system </Th> </Tr> <Tr> <Th> </Th> <Td> Android (73%) </Td> <Td> Windows (83%) </Td> </Tr> <Tr> <Th> </Th> <Td> iOS (20%) </Td> <Td> OS X (13%) </Td> </Tr> <Tr> <Th> </Th> <Td> Nokia (1%) </Td> <Td> Linux (2%) </Td> </Tr> <Tr> <Th> </Th> <Td> Windows (1%) </Td> <Td> Chrome OS (1%) </Td> </Tr> </Table> <Tr> <Th> Place </Th> <Th> Mobile system </Th> <Th> Desktop system </Th> </Tr>

Where does the operating system reside on a computer