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

Feasebility study, what are the feasibility study of online result manageme...

what are the feasibility study of online result management system?

Loosely coupled systems, Loosely Coupled Systems These systems do not d...

Loosely Coupled Systems These systems do not distribute the global memory because shared memory concept gives rise to the difficulty  of memory conflicts, which in turn slows d

In java system.out is an object of which type, In Java System.out is an obj...

In Java System.out is an object of type? In Java System.out is an object of form Print Stream.

What are threaded binary trees, What are threaded binary trees? A Threa...

What are threaded binary trees? A Threaded Binary Tree is a binary tree in which each node that does not have a right child has a THREAD (in real sense, a link) to its INORDER

How the system would work in real time- simulation, How the system would wo...

How the system would work in real time -  Sensors in/near road gather data (these can be infra-red/light sensors, pressure sensors, induction loops etc.) -data is generally num

What are the benefits of micro programmed control, a. What are the benefits...

a. What are the benefits of hardwired and micro programmed control? b. Sketch neat diagram of single bus organization of CPU showing ALU, all types of registers and the data pat

What is the use of hypertext links in internet access, What is the use of h...

What is the use of hypertext links in Internet access? Use of Hypertext links in Internet access: From the user’s view point, the Web comprised a vast, worldwide collecti

Explain what are design patterns, Design Patterns are easy and elegant solu...

Design Patterns are easy and elegant solutions of commonly having problems in software design. Design Patterns make it simpler to reuse successful designs and architectures of expe

Explain is cgi a script or a program, The distinction is semantic. Traditio...

The distinction is semantic. Traditionally, compiled executables (binaries) are known as programs, and interpreted programs are usually known as scripts. In the context of CGI, the

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