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

Superscalar processors, Superscalar Processors In scalar processors, on...

Superscalar Processors In scalar processors, only one instruction is implemented per cycle. That means only single instruction is issued per cycle and only single instruction i

Write a short note on structure chart, Write a short note on structure char...

Write a short note on structure chart.    Structure Chart is an significant program design method and it shows all components of code in a hierarchical format

Tools for performance measurement, Tools for Performance Measurement Th...

Tools for Performance Measurement The reason behind these algorithms has been to gain a speed up and improve the performance. After the parallel algorithm has been written and

Describe how management information systems, Question: a) Why do we u...

Question: a) Why do we use the Internet as the new distribution channel for e-banking products and services? b) In the context of e-banking or e-commerce, outline some o

Set up the site structure, Structuring the Web site is first step towards b...

Structuring the Web site is first step towards building the corporate Web site. Structuring includes creating a folder that includes all our picture files, text files and database

Explain fundamental models of inter process communication, Explain the two ...

Explain the two fundamental models of inter process communication. Two kinds of message passing system are given as: (a) Direct Communication : Along with direct communicat

Example calculation of entropy, Example Calculation: If we see an exam...

Example Calculation: If we see an example we are working with a set of examples like S = {s 1 ,s 2 ,s 3 ,s 4 } categorised with a binary categorisation of positives and negati

Classify process and differentiate program, Classify Process, differentiate...

Classify Process, differentiate program, process A process maybe concerned to be a program being run. A program isn't a process of itself; it's a passive Entity while the proce

Design a nand-to-and gate network, Q Use as few gates as possible, design a...

Q Use as few gates as possible, design a NAND-to-AND gate network that realize the following Boolean algebra expression. ABCD + A'BC'D + A'BC'D' + A'BCD + (A'B'C'D' + A'BCD')

Implement simplified expression using nor gates only, Q. For function F(x,y...

Q. For function F(x,y,z) = ∑m (1,2,3,5,6) using TRUTH TABLE only 1. Find POS expression 2. Implement this simplified expression using two level OR-to-AND gate network 3. I

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