IBM is the world's largest manufacturer of computer hardware, others being Hewlett Packard, Wang and Sinclair. They are known for the IBM 7030 second generation supercomputer, the 360 series of mainframes first released in 1964, and the 5100 series of microcomputers first manufactured in 1975. Around 1977, they licenced their microprocessor to other manufacturers, thereby boosting, and some would say triggering, the microcomputer revolution. They have a monopoly on several aspects of their technology, fiercely defend their patents and are known for being conservative and cautious. It has been alleged that they hold back innovation in information technology to prevent losing their supreme position in the market. However, they are probably also one of the few companies with enough resources to produce the large-scale integration integrated circuits on which many of today's digital devices depend.