In paging, It is not necessary to add page offset to the starting address of the page frame to generate a physical address

Question

In the answer(in the book), I am not getting the following-

"The starting address of an n-bit page frame is a multiple of 2^n. Thus, the bit pattern of the frame's starting address consists of the frame number followed by n 0's."

Please explain.

Answer 1

You need another book.

The starting address of an n-bit page frame is a multiple of 2^n. Thus, the bit pattern of the frame's starting address consists of the frame number followed by n 0's."

That's nonsense or at least partial nonsense. It presumes that page frames are addressed, rather than indexed.

In a real mode, memory is addressed, but there are no page frames. When logical memory translation is used, page frames are indexed on every system I have seen.

If page frames were addressed as suggested in your book, 1) A system could not have more physical memory than can be addressed using the CPU's word size; and 2) The page tables would be unnecessarily large because they would have to account for both the full address of the page frame AND any overhead bits.

Normally, page tables use the spare bits from the page size for page management overhead.

IF the first byte in a page frame were to be accessed in real mode, then such a byte would address would be a multiple of the page size (which is always a power of 2). Thus, the lower bits in the address would be some string of zeros. But in virtual/logical translation page frames do not have addresses.

I do not understand why these operating systems books insist on confusing the subject.