http://blog.csdn.net/w57w57w57/article/details/6626840
http://people.cs.umass.edu/~verts/cs32/endian.html
http://zh.wikipedia.org/wiki/%E6%9C%89%E7%AC%A6%E8%99%9F%E6%95%B8%E8%99%95%E7%90%86
http://en.wikipedia.org/wiki/Endianness
http://www.cs.umd.edu/class/sum2003/cmsc311/Notes/Data/endian.html
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lock implementation & principle
sync vs async principle