1 Discuss some issues in the design of the paging daemon 2 D

1. Discuss some issues in the design of the paging daemon.

2. Discuss the pros and cons of using cheap NAND (think the cheap USB thumb drives, which might exceed their write capacity after a mere 20 overwrites or so) for bulk archival storage. Facebook, for example, has been rumored to be considering this.

Solution

Answer :

Discuss some issues in the design of the paging daemon.

Answer :

1.Paging daemon begins selecting pages to evict using a page replacement alogorithm.

2.Paging daemon is a background process

3.1.Local versus Global Allocation Policies: A global policy is one in which the choice of victim is made among all pages of all processes.

    2.Original configuration

    3.Local page replacement

    4.Global page replacement

4.A local PRA is one which victim page is chosen among the pages of same process that requires a new page.

5. The number of pages for each process is fixed.

6.Page Fault Rate :

    1.Page fault rate as af function of the number of page frames assigned.

    2.A program causing page faults every few instructions is said to be thrashing.If a process keeps accessing random new pages,then it is hard to anticipate what it will use next.

   7.Load Control :

     1.To reduce the overall memory pressure ,we must reduce the multiprogramming level.We have a connection between memory management and process management.

   2.Reduce number of processes competing for memory,swap one or more to disk.

   8.Page size :1.small page size:less internal fragmentation

                       2.A very large page size leads to very few pages.Process will have Many faults if using daemond paging and the process frequently references more regions than frames.

                      3.Disadvantage is programs need many pages,larger page tables.

9.