physical device address

基本解释

The never-changing MAC provides a specific, reliable address for a physical device.
而永不变化的MAC地址给物理设备提供了一个独特可靠的地址。
Each guest operating system is mapped through the /dev/kvm device, having its own virtual address space that is mapped into the host kernel's physical address space.
每个来宾操作系统都是通过 /dev/kvm 设备映射的，它们拥有自己的虚拟地址空间，该空间映射到主机内核的物理地址空间。
A MAC address is a unique character string, and since it identifies a specific physical device -- one individual NIC -- the MAC address, by convention, never changes for the life of the NIC.
一个MAC地址是一个独一无二的字符串。由于它标识一个独特的物理设备——一个唯一的网卡——MAC地址，按照约定，在网卡中将永不会改变。

Security solutions based on physical infrastructure, and policy expressed in terms of a particular device, the corporate PC, an IP address, network port, or application protocol are becoming useless in a mobile, borderless world.
FORBES: Going Mobile: Security in the Age of Ubiquity