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

Briefly explain about file system implementation, Briefly explain about fil...

Briefly explain about file system implementation? Several on-disk and in-memory structures are used to execute a file system. On disk, the file system may have information abou

What is a file path name, What is a file path name? A list of the subdi...

What is a file path name? A list of the subdirectories, directories, and files we must traverse to reach a file from the root directory.

What is the purpose of system calls, What is the purpose of system calls? ...

What is the purpose of system calls? System calls permit user-level processes to request services of the operating system.

If a process is blocked, There is a process bloacked by a semaphore and no ...

There is a process bloacked by a semaphore and no other process in the ready queue, can the blocked process get back to the ready queue without the semsignal() function?

Explain lru approximation page replacement in detail, LRU approximation pag...

LRU approximation page replacement In this we utilize the reference bit associated with the page entry to choose a page to be removed. The various algorithms used for the imp

Define segmentation, Define Segmentation  The memory allocation method...

Define Segmentation  The memory allocation method subject to “external” fragmentation is Segmentation.

How many cubic feet of storage space would require, Q. Presume that we agr...

Q. Presume that we agree that 1 kilobyte is 1,024 bytes 1 megabyte is 1,0242 bytes and 1 gigabyte is 1,0243 bytes. This progression carries on through terabytes, petabytes, and ex

Components of the r/e system, What components of the R/e system initiate th...

What components of the R/e system initiate the start of background jobs at the specified time? The batch scheduler initiates the begin of background job.  The dispatcher then s

Explain what isam, Explain what ISAM is. Indexed sequential access meth...

Explain what ISAM is. Indexed sequential access method. The file is stored in sorted order. ISAM has a master index file, indicating in what part of another index file the key

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