Implementing protection with virtual memory, Computer Engineering

Assignment Help:

Implementing Protection with Virtual Memory - computer architecture:

To enable the operating system to implement protection in the VM system, the HW have to:

I. Support at least 2 modes that denoted whether the running process is a user process (executive process) or an operating system process (kernel/supervisor process).

II. Provide a part ion of the CPU state that a user process may read but not write (includes supervisor mode bit).

  • Provide mechanism where the CPU may go from user mode to supervisor mode (accomplished by a system call exception) and vice versa (return from exception instruction).

o   Only operating system process may change page tables. Page tables are held in operating system address space thereby preventing a user procedure from changing them. 

o   When processes desire to share information in a restricted way, the OS have to assist them.

o   The write access bit (in both the TLB and the page table) can be used to limit the sharing to only read sharing.

 


Related Discussions:- Implementing protection with virtual memory

Automatic switching system and manual switching system, Discuss the advanta...

Discuss the advantages of automatic switching systems over manual switching system. Automatic switching systems have some advantages over the manual exchanges: 1. In a manua

Dbms, what is cascading rolback?

what is cascading rolback?

What are the server specific middle wares, What are the server specific mid...

What are the server specific middle wares? Server specific middle wares. Their role in e-commerce. Additional features needed by e-commerce server. Middleware is the term of

Dfd, dfd for big bazaar

dfd for big bazaar

What are the disadvantages of a smart card, What are the disadvantages of a...

What are the disadvantages of a Smart Card? Disadvantages of Smart Cards are as follows: a. The value of money can be depleted and recharged. b. Customers should keep

What is the difference between swapping and paging, What is the difference ...

What is the difference between Swapping and Paging? Swapping: Entire process is moved from the swap device to the major memory for implementation. Process size must be less t

Process of an e-mail transfer across the internet, Q. Process of An e-mail ...

Q. Process of An e-mail transfer across the Internet? When you open your mail client to read your e-mail, this is what normally happens: 1. Mail client (Netscape Mail, Micro

Explain the term- tracker ball and braille printers, Explain the term- Trac...

Explain the term- Tracker ball and Braille printers Tracker ball Easier to use than a mouse if people have problems using their arms and hands or if they have a coordinati

Multiple instruction and single data stream (misd), Multiple Instruction an...

Multiple Instruction and Single Data stream (MISD) In this association, multiple processing elements are structured under the control of multiple control units. Each control un

Information system today, What is the benefit of MITRE''s evolutionary appr...

What is the benefit of MITRE''s evolutionary approach to KM?

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