Among these vendors, there were only two large vendors with many industrial companies. For microprocessors, Intel supplied 80% of the market until competitors, such as Advanced Micro Devices and VIA Technologies, entered the market in the 1990s. However, even as competitors entered, Intel managed to remain the market leader with more advanced technology, manufacturing scale and powerful brand. Also for operating systems, Microsoft has provided the operating systems for more than 90% of PCs. One of the biggest successes of Windows, Windows 7, was released in 2009. Another competitor of Microsoft was Apple which created its own operating system called OS X v 10.6 Snow Leopard. Additionally, these suppliers offered highly differentiated products. For Intel, they had more advanced technology than their competitors, making their products more up to date with technological developments. For microprocessors, Windows was very different from Snow Leopard, containing different layouts and programs. Although these two features may not seem to make much difference, they are what attracted consumers to Apple and Windows products. They created a difference in what the consumer would buy. Second, there were no close substitutes for the suppliers' products because the functions of the microprocessors and operating systems were not substitutable. Finally, the costs of changing microprocessors and operating systems would be high, as they would have to develop all new computers to incorporate the new operating system and have the ability to run the computer further.