discussion midterm question
Download
Skip this Video
Download Presentation
Discussion/Midterm Question

Loading in 2 Seconds...

play fullscreen
1 / 6

Discussion/Midterm Question - PowerPoint PPT Presentation


  • 73 Views
  • Uploaded on

Discussion/Midterm Question. Assume a system with a two level page table. The virtual memory address space is 32 bits and the physical memory address space is 16 bits. . Factors in determining size of page. Page table fits on one page Equal sized L1 and L2 page tables

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Discussion/Midterm Question' - hidi


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide2

Assume a system with a two level page table. The virtual memory address space is 32 bits and the physical memory address space is 16 bits.

factors in determining size of page
Factors in determining size of page
  • Page table fits on one page
  • Equal sized L1 and L2 page tables
  • Size of a page table entry
    • size of physical memory (16 bit address space)
    • bookkeeping bits
fitting a page table on one page
Fitting a page table on one page

(size of page) (size of page table)

  • Size of page
  • # of PTE
  • Size of PTE

(size of page table) =

(# of PTEs) * (size of PTE)

  • (2offset)
  • (2(32-offset)/2)

(16 bits - offset + bookkeeping ≈ 1-4 bytes)

2offset ≥ 2(32-offset)/2 (assuming 1 byte PTE)

offset ≥ 10.667

fitting a page table on one page1
Fitting a page table on one page

(size of page) (size of page table)

  • Size of page
  • # of PTE
  • Size of PTE

(size of page table) =

(# of PTEs) * (size of PTE)

  • (2offset)
  • (2(32-offset)/2)

(16 bits - offset + bookkeeping ≈ 1-4 bytes)

2offset ≥ 2(32-offset)/2*22 (assuming 4 byte PTE)

offset ≥ 12

12 bit offset works under either assumption

solutions
Solutions
  • Offset = 12
    • 4KB pages
  • VPN1 = VPN2 = 10
    • 210 entries per page table
ad