在计算机存储介质上，LUN仅是分配给逻辑单元的号码。

In computer storage, a LUN is simply the number assigned to a logical unit.

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代码中有一些对可变的系统事件（比如说内存警告和存储单元分配）的回调。

There are some callbacks for variable system events such as memory warnings and the de-allocation.

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这些专用的方法包括对象的分配，存储单元分配以及初始化。

These special methods include allocation, deallocation, and initialization of objects.

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