Single-level page tables, Operating System

Assignment Help:

As mentioned above, page tables, are lookup tables mapping a process' virtual pages to physical pages in RAM. How would one implement these page tables?

The most straightforward approach would simply have a single linear array of page-table entries (PTEs). Each PTE contains information about the page, such as its physical page number ("frame" number) as well as status bits, such as whether or not the page is valid, and other bits to be discussed later.

If we have a 32-bit architecture with 4k pages, then we have 2 pages, as discussed in the last lecture. If each PTE is 4 bytes, then each page table requires 4 Mbytes of memory. And remember that each process needs its own page table, and theremay be on the order of 100 processes running on a typical personal computer. This would require on the order of 400 Mbytes of RAM just to hold the page tables on a typical desktop!

Furthermore, many programs have a very sparse virtual address space. The vast majority of their PTEs would simply be marked  invalid.Clearly, we need a better solution than single-level page tables.


Related Discussions:- Single-level page tables

Explain quick fit algorithams, QUICK FIT ALGORITHAMS Here we keep apart...

QUICK FIT ALGORITHAMS Here we keep apart lists for holes and processes. Therefore this reduces the searching time for holes Hole list and Process list. If we organize the li

Operation on file system, Question : The file system is the most visibl...

Question : The file system is the most visible aspect of an operating system. It provides the mechanism for on-line storage and access to both data and programs of the operatin

Explain advantages and inconveniences of ult, ADVANTAGES AND INCONVENIENCES...

ADVANTAGES AND INCONVENIENCES OF ULT Advantages: Thread switching doesn't involve the kernel - no mode switching Scheduling is able to be application specific -

What is multitasking, What is Multitasking? Multitasking provides power...

What is Multitasking? Multitasking provides power to users by offering them to run multiple applications at once. The applications are loaded into memory and appear to the user

Batch oriented and interactive operating system., properies of Batch orient...

properies of Batch oriented and interactive operating system.

Briefly describe the producer-consumer problem, Question: a) Each proc...

Question: a) Each process is represented in the operating system by a process control block (PCB). The PCB contains many pieces of information associated with a specific proce

Example of producer consumer - semaphore, Now let's implement bounded produ...

Now let's implement bounded producer-consumer with semaphores, a Coke machine which is initially empty: semaphore sem_mutex = 1 // binary semaphore for mutual exclusion, 1==unlo

What are the operations of a directory, Operations that are to be performed...

Operations that are to be performed on a directory are Search for a file: We are able to find all files whose names match a exact pattern. Create a file: New files requi

What is meant by context switch, What is meant by context switch? Switc...

What is meant by context switch? Switching the CPU to another process needs saving the state of the old process and loading the saved state for the latest process. This task is

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd