purpose of paging the page tables in os
Page table There is normally one hash table, contiguous in physical memory, shared by all processes. A per-process identifier is used to disambiguate the pages of different processes from each other. It is somewhat slow to remove the page table entries of a given process; the OS may avoid reusing per-process identifier values to delay facing this. Alternatively, per-process hash tables may be used, but they are impractical because of memory fragmentation, which requires the tables to be pre-allocated.
Page numbering In books, some pages, known as blind folios,[1] of the front matter and back matter are numbered, but the numbers are not always printed on the pages. Publishers are not consistent about how they number the pages of their books. Some publishers stick with the default numbering of the tool they are using, which is typically to number the first page of the front matter as one and all pages after that in a consecutive order. When publishers wish to distinguish between the front matter and the story, the initial title pages are not numbered, the front matter is numbered using small Roman numerals (i, ii, iii, etc.) and the first page of the story or main content begins with one. The title page of the story is not numbered, but if a story is broken into multiple parts (Part I, Part II, etc.), the title page for the section may be included in the numbering but not shown on the page. The first page of Chapter One would then be numbered as page three rather than page one as would be the normal case.