1/09/2008

Memory Addressing (2)

1. Linux prefers paging to segmentation. So the 2.4 version of linux uses segmentation only when required by the 80x86 architecture.

2. The segments used by Linux
1) A kernel segment: the corresponding Segment Selector is defined by the __KERNEL_CS macro.
2) a kernel data segment: the corresponding Segment Selector is defined by the __KERNEL_DS macro.
3) a user code segment: the corresponding Segment Selector is defined by the __USER_CS macro.
4) a user data segment: the corresponding Segment Selector is defined by the __USER_DS macro.
5) a Task State Segment (TSS) for each processor.
6) a default Local Descriptor Table (LDT)
7) four segments related to Advanced Power Management (APM) support.

3. Contiguous addresses within a page are mapped into contiguous physical addresses.

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