Question

 Write a short note on Paging.

Answer 1

(1) It is noncontiguous allocation memory management scheme. In various contiguous allocation schemes a problem of fragmentation is there. This is the best method to solve that problem.
(2) The physical main memory is divided into equal sized page frames and the logical space of the program is divided into equal size pages. The page and frame size is same so that a page can exactly fit into a page frame. The assignment of page to any page frame is free .
(3) The addresses which program refers are called virtual or logical addresses. In reality the program may be loaded at different memory locations are called physical addresses.
(4) When any program has to be executed its pages are loaded into any available frames and the page map table is used to translate from user pages to memory frames.

(5) Virtual addresses consist of two parameters, a virtual page no. and displacement within the page. During translation the virtual page number should be converted into physical page no.