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

Explain turing reducibility, Explain Turing reducibility?  Exponential ...

Explain Turing reducibility?  Exponential time algorithms typically happens when we solve by searching by a space of solutions known as brute -force search

Organisational inertia - obstacle to information system, Organisational Ine...

Organisational Inertia - Obstacle To Information System This is most easily understood as problems of change and culture. Like any change process technology led change will be

State about an active graphics device, State about An active graphics devic...

State about An active graphics device An active graphics device allows the user to communicate with the computer graphically. Generally, this implies that the user is supplyin

Trusted publisher, State the criteria which a trusted publisher should meet...

State the criteria which a trusted publisher should meet before adding him? Ans) The following criteria should be met by the publisher before adding him to the list. ? The

Explain simple telephone communication system, Explain simple telephone com...

Explain simple telephone communication system with circuit and equation of current flow in microphone? Simple Telephone Communication: In the simplest type of a telephone cir

Define the meaning of document and finger print, a. Define the meaning of "...

a. Define the meaning of "Document & Finger print" and "Message & Message Digest". What's the difference among the 2 pairs? b. Describe Davies Meyer scheme with diagram. c. W

Basic working of network layer, Q. Basic working of Network layer? Net...

Q. Basic working of Network layer? Network layer: Network layer is responsible for routing a packet within the subnet that is, from source to destination nodes across numerou

Explain the role of a bus arbiter in a multiprocessor, Explain the role of ...

Explain the role of a bus arbiter in a multiprocessor configuration. Bus arbiter: Which functions to resolve priority between bus masters and allows only one device at a time t

What will be the output of JK flipflop for J = 0 and K=1, For JK flipflop J...

For JK flipflop J = 0, K=1, the output after clock pulse will be ? Ans. J=0 and K=1, such inputs will reset the flip-flop, after the clock pulse. Therefore whatever be the earlie

8085 programs, what is the theory used to check whether a number is negativ...

what is the theory used to check whether a number is negative or positive?

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