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

What are the different types of semaphore?, What are the different types of...

What are the different types of semaphore? Principally the semaphore is able to be classified into two on the basis of their values a)      Counting semaphore: In counting s

Linux, server configure

server configure

Allocation techniques, Since most of the programs require a lot of memory a...

Since most of the programs require a lot of memory allocation/deallocation, we expect the memory management to be fast, to have low fragmentation, make good use of locality, and be

Explain the real time operating system, Explain the Real Time Operating Sys...

Explain the Real Time Operating System A real-time operating system comprises definite, fixed time constraints. Processing should be done in the defined constraints, or the sys

Define thrashing, Define thrashing. Thrashing is the accident of high p...

Define thrashing. Thrashing is the accident of high page traffic and low CPU utilization. It is observed that the cause of thrashing is an under-commitment of memory to program

Explain indexed allocation, Indexed allocation Indexed allocation bring...

Indexed allocation Indexed allocation bringing all the pointers together into one location: the index block. Every file has its own index block, which is an array of disk-block

What is a semaphore, What is a semaphore? A semaphore 'S' is a synchron...

What is a semaphore? A semaphore 'S' is a synchronization tool which is  an integer value that, apart from initialization, is accessed only by two standard atomic operations; w

Can a direct access file be read sequentially, Can a direct access file be ...

Can a direct access file be read sequentially? Explain. Yes. Keep a counter, cp, initially set to 0. After reading record cp, increment cp.

Microsoft, Discuss the high barriers to entry in the market for PL operatin...

Discuss the high barriers to entry in the market for PL operating systems

What is page fault, Problem: a) The CPU can access 2 storage devices di...

Problem: a) The CPU can access 2 storage devices directly. What are these 2 storage devices? b) Define 2 key issues involved in memory management. c) How do processes sha

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