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

Student, Explain how the os implements virtual memory phenomenon.

Explain how the os implements virtual memory phenomenon.

Cpu, Some CPUs provide for more than two modes of operation. What are two p...

Some CPUs provide for more than two modes of operation. What are two possible uses of these multiple modes?

Introduction to paging, We will brie?y introduce paging to ?nish off this l...

We will brie?y introduce paging to ?nish off this lecture. When a process is loaded, not all of the pages are immediately loaded, since it's possible that they will not all be need

Linux operation system, wat are the commands used for creating the file hie...

wat are the commands used for creating the file hierarchy

Compression regarding the file system in windows 2000, Write short note on ...

Write short note on compression regarding the file system in Windows 2000. NTFS is able to perform data compression on individual files or on all data files in a directory. To

Determine a critical section is a program segment, Determine a critical sec...

Determine a critical section is a program segment  Critical section is where shared resources are accessed

What is internal fragmentation?, What is internal fragmentation? Consid...

What is internal fragmentation? Consider holes of 20k assume the process requests 18 bites. If we allocate accurately the request block, we are left with a hole of 2k. The over

What are placement and replacement algorithms, Placement algorithms :calcu...

Placement algorithms :calculate where in available real-memory to execute a program. Common functions are next-fit, first-fit, and best-fit. Replacement algorithms :are

Explain hashed page table method, Hashed page table method A general ap...

Hashed page table method A general approach for managing address spaces larger than 32 bits is to use a hashed page table with the hash values being the virtual-page number.

What kernel provide for an effective user level thread, 1. What must a kern...

1. What must a kernel provide for an effective user-level thread implementation? 2. With respect to the quantum q in a scheduling algorithm, explain and discuss the impact of th

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