https://qooah.com/2012/10/22/google-%e7%99%bc%e4%bd%88%e6%9c%83%e5%89%8d%e9%a0%90%e6%b8%ac-%e5%85%a8%e6%96%b0-nexus-%e7%b3%bb%e5%88%97%e5%92%8c-android-%e6%93%8d%e4%bd%9c%e7%b3%bb%e7%b5%b1-2/