Segmentation with Paging:
Both paging and segmentation have their advantages and
disadvantages. It is better possible to combine these two schemes to improve on
each. The combined scheme was ‘Page the
segments’. Each segment in this scheme is divided into pages and each
segment maintains a page table. So, the
logical address is divided into 3 parts <S, P, D>.One is the segment
number (S), second is the page number
(P) and another is a displacement or
offset (D). Consider the following fig:
Fig: Paged Segmentation
The logical address space is divided into three segments
number from 0 to 2. Each segment maintains a page table. The mapping between
page and frame is done by page table. For ex: the frame number 8 shows the address
(1, 3); where 1 stands for segment and 3 stands for page number. The main
advantage of this scheme is to avoid fragmentation. It supports user view of
memory. The hardware support of this combined scheme is shown in the following
figure.
Fig: Paged segmentation memory
management scheme
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