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Most architectures allow a process to execute in at least two modes: kernel and user. In the kernel mode a process can set up translation tables, change the processor state that determines the mode of the processor, use the kernel translation table and execute other privileged instructions, while in the user mode it uses the process' translation table and instructions. Thus these architectures allow a process to switch between the access rights of the user and the kernel.

Prasun Dewan
Mon Nov 4 12:08:34 EST 1996