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 arithmetic data processing instructions, Q. Explain Arithmetic Data...

Q. Explain Arithmetic Data Processing Instructions? These instructions carry outlogical and arithmetic operations on data. Arithmetic: The four fundamental operations are

Computer science, Read in integers until a zero is read in. Keep a total o...

Read in integers until a zero is read in. Keep a total of both the quantity and the sum of the negative integers and the positive integers. Once a zero is read in (signifying the

Difference among activity and sequence diagram, a. Activity diagram: Activi...

a. Activity diagram: Activity diagram is used for functional modelling. Captures the process flow. b.  Sequence diagram :  Sequence diagram is  used for dynamic modeling.

Explain the potential role of information technology, Question 1: Descr...

Question 1: Describe the five maturity levels of KM that an organization faces when adopting the Frid's KM framework. Question 2: (a) Describe three major issues that

Find the minimum sop and pos expression, Find the minimum SOP and POS expre...

Find the minimum SOP and POS expression for the following functions using Karnaugh Map and realize the expression using appropriate gates. Also realize SOP form using NAND-to-NAND

What is ale and explain the functions of ale in 8085, ALE-> Address latch e...

ALE-> Address latch enable...In the case of microcontroller (8051)& microprocessor 8085 the data line and low order 8 bit address lines are multiplexed. In order to getting address

Which interface controls what is shown on the p.c., Which interface control...

Which interface controls what is shown on the p.c.? Presentation Interface  controls what is shown on the p.c

What is a session in php, A session is a logical object formed by the PHP e...

A session is a logical object formed by the PHP engine to permit you to preserve data across subsequent HTTP requests. There is only one session object available to your PHP scr

Slower layer to a faster layer, Given a four level hierarchical storage sys...

Given a four level hierarchical storage system consisting of: cache,  primary storage, secondary storage, and tertiary storage. Suppose the following:  programs may be executed on

What is memory controller, What is memory controller? A memory controll...

What is memory controller? A memory controller is a circuit which is interposed among the processor and the dynamic memory. It is used for performing multiplexing of address bi

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