MMU Memory Management Unit, translates virtual to physical addresses and provides access permission control.

内存管理单位，把虚地址转化为物理地址并且提供访问许可控制。

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The functions of the MMU are to control the various memory systems, translate the virtual addresses into physical addresses and control the access permission.

MMU的功能是控制各种存储系统的工作并将虚地址转换成物理地址，以及控制存储器访问权限。

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The media access control (MAC) protocol of mobile Ad Hoc networks (MANETs) is closely-related with its physics layer, most MAC protocols request the capability of carrier sense in physical layer.

无线自组网的介质访问控制(MAC)协议是与物理层密切相关的，大多数MAC协议都要求物理层具备载波感知能力。

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But moving beyond segmentation and basic access control, the virtual world provides opportunities for innovative security that the physical world simply cannot fathom.

FORBES: Best of Times, Worst of Times: Is Virtualization in the Data Center a Problem or an Opportunity?