sizeof usage & big / little endian

http://blog.****.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