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

Operating system, The term Operating System (OS) is often misused. It is co...

The term Operating System (OS) is often misused. It is common, for example, for people to speak of an OS when they are in fact referring to an OS and to a set of additional applica

An operating system for a real-time environment, Q. What is the major diffi...

Q. What is the major difficulty that a programmer should overcome in writing an operating system for a real-time environment? Answer: The major difficulty is keeping the oper

What are overlays, What are overlays? To enable a process to be larger ...

What are overlays? To enable a process to be larger than the amount of memory allocated to it, overlays are used. The idea of overlays is to keep in memory only those instructi

Why is rotational optimization no longer consequently useful, UNIX systems ...

UNIX systems utilized to use disk-layout optimizations based on the rotation position of disk data however modern implementations including Linux simply optimize for sequential dat

Catalogue the design goals of windows xp, Q. Catalogue the design goals of ...

Q. Catalogue the design goals of Windows XP. Answer: Design goals comprise security and reliability and Windows and POSIX application compatibility with high performance and ex

What is super block, What is super block A partition control block have...

What is super block A partition control block have partitions details, such as the number of blocks in the partition, size of the blocks, free-blocks and free-block pointers an

Hardware and software requirements for virtual memory?, What are the hardwa...

What are the hardware and software requirements for virtual memory? The hardware required for virtual memory is a secondary memory and page table. The page table should have th

Safety algorithm and resource request algorithm, Safety algorithm : This is...

Safety algorithm : This is to make sure if the system is in safe state or not. It may need an order of m x n2 operation to determine if the state of the system is safe or not.

Model, list trhe various classification of model and types?

list trhe various classification of model and types?

Windows admin need it, Windows admin need it Project Description: We ...

Windows admin need it Project Description: We want to protect an executable on operating system level , so the process could be visible among all users while the executable r

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