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

How free-space is managed using bit vector implementation, How free-space i...

How free-space is managed using bit vector implementation? The free-space list is implemented as a bit map or bit vector. Each block is shown by 1 bit. If the block is free, th

What are the phases of background processing, What are the phases of backgr...

What are the phases of background processing? Phases are:- Job Scheduling. Job Processing. Job Overview.

Explain acyclic graph directories and its implementation, Acyclic Graph Dir...

Acyclic Graph Directories In this kind of directory structure the shared directories or files can exist in the file system in two or more places at once. A tree structure excl

Briefly discuss on bankers algorithm, Briefly discuss on Bankers algorithm?...

Briefly discuss on Bankers algorithm? The resource-allocation graph algorithm is not applicable to a resource-allocation system with multiple examples  for each resource type.

Binary arithmetic, The principle is that of ordinary addition; however reme...

The principle is that of ordinary addition; however remember the highest number is 1.   Calculate the following:                             11001 +                           11

Write a program to demonstrate the memory leak problem, Write a program (wi...

Write a program (with the programming language and on the platform of your choice) to demonstrate the memory leak problem (see http://en.wikipedia.org/wiki/Memory_leak for detail

Define the os/2 threads code, Define the OS/2 threads code The sample p...

Define the OS/2 threads code The sample program in Listing is very similar to the NetWare example. OS/2 commands are substituted for the pseudocode commands controlling thread

Explain fixed partitioning, Explain fixed partitioning. Partitioning ar...

Explain fixed partitioning. Partitioning are the simpler techniques that don't involve virtual memory. Partitioning has been used in numerous variations in operating systems.

Explain the spawnlp functions used in the netware, Explain the Spawnlp Func...

Explain the Spawnlp Functions Used in the NetWare Spawnlp(flags, execName, arg0,...)  The Spawnlp function is used to load  a NetWare executable file (NLM) specified by exec

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