Low memory (896M-) kernel paging directory

1.         3G~4G logical address which is used only in kernel mode

2.         Kernel main page directory is setup to translate the logical address to physical address

3.         No middle page table exists in order to save memory by setting the page size to 4M

4.         Entry 768~992 in page directory is used

5.         The kernel main page directory is used as a template by user process and kernel thread