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

What qualifications needs to be an security professionals, Qualifications o...

Qualifications of security professionals For the security professionals, it is essential that they have adequate freedom to check the security measures and enforce them and

Explain assembly language, Explain Assembly Language This is a family o...

Explain Assembly Language This is a family of low-level language for programming computers, microprocessors, microcontrollers etc. They implement a symbolic sign of the numeric

Explain signed binary number system, Explain signed binary number system. ...

Explain signed binary number system. Ans. Signed Binary Numbers: In decimal number system positive numbers are signified by (+) sign and negative numbers are represented b

Constructor, what is meant by private copy constructor

what is meant by private copy constructor

TITLE: Signals for digital communications, DETERMINE ANALYTICALY IF THE SIG...

DETERMINE ANALYTICALY IF THE SIGNAL IS PERIODIC OR NOT - X[n] = 4Cos(Pi n)

the bias and standard error , A random variable (X) is modelled as an expo...

A random variable (X) is modelled as an exponentially distributed with mean 30 units. Simulate N = 50 samples from this distribution, and every sample must have m = 20 simulated va

Illustrate does gas have density, Q. Illustrate does gas have density? ...

Q. Illustrate does gas have density? Answer:- Gas in addition to everything in the universe has density though some densities are not either too high or too low to be dete

Do we require an x server to run in batch mode for gimp, Yes, you have to h...

Yes, you have to have some form of X server (unless you're running Windows, of course). It requires an X server for image processing, and for font manipulation. Though, if you wish

Define top-down parsing techniques, Define Top-down parsing Techniques ...

Define Top-down parsing Techniques Top-down parsing can be observed as an attempt to find left-most derivations of an input-stream through searching for parse trees using a top

Derivatives and applications of derivatives, What can you say about the exi...

What can you say about the existence of a stationary point in the interval [ 1; 3] for the function f (x) = x 2 2x 3.

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