Combining segmentation and paging
Last updated
Last updated
Segmentation, taken alone, can have some drawbacks:
It may result in external fragmentation.
A growing segment can impose a change in its location.
Merging segmentation and paging can solve these issues.
First, the logical address space of a process is partitioned into segments.
Then, each segment is divided into pages.
However, this introduces a growing complexity.
The MMU must contain 3 base registers and 1 limit register.
1 base register for the segmentation table.
1 limit register for the segmentation table.
1 base register for the page table.
1 base register for the memory frame.
Access to memory unfolds into 3 steps:
Access to the segmentation table.
Access to the page table.
Access to the physical address.
Entry of the segmentation table.
Entry of the page table.
The perm field is now associated with the segment.
