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 various process scheduling concepts, What are the various proc...

What are the various process scheduling concepts? a) Scheduling queues with diagram b) Queuing diagram c) Schedulers d) Context switch with diagram

What are tree-structured directories, What are Tree-structured directories ...

What are Tree-structured directories We can generalize the directory structure to a tree of arbitrary height. This permits the user to create their own sub directories and to c

Explain types of file allocation- linked list allocation, Linked list alloc...

Linked list allocation: At this time the blocks are stored using linked lists. The block size require not be the same. Thus internal fragmentation is avoided. Consider

What is the use of boot block, What is the use of boot block? For a com...

What is the use of boot block? For a computer to begin running when powered up or rebooted it requires having an initial program to run. This bootstrap program tends to be easy

What is meant by the term affinity in processor sheduling, Question: (a...

Question: (a) Answer the following questions based on the code snippet below. 1. int main (int argc, char *argv[]) 2. { 3. 4. pid_t processId; 5. 6. processId =

Demand paging, Demand paging gives that pages could only be brought into ...

Demand paging gives that pages could only be brought into memory if the running process acts them. This is usually referred to as lazy evaluation as only those pages operated by

Aggregate planning, Prepare a report that motivates alternatives reactive s...

Prepare a report that motivates alternatives reactive strategies that can be used by wind Mud clothing factory

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