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 non-adapting routing, Explain non-adapting routing. Systems whi...

Explain non-adapting routing. Systems which do not implement adaptive routing are explained as using non-adapting or static routing, which routes by a network are explained by

Why do we need dma, Why do we need DMA? DMA is used to transfer the blo...

Why do we need DMA? DMA is used to transfer the block of data directly among an external device and the main memory without the continuous intervention by the processor.

Basic tradeoff of concerns for instruction set design, Q. Basic Tradeoff of...

Q. Basic Tradeoff of concerns for instruction set design? Basic Tradeoff: Smaller instruction (less space) vs. desire for more powerful instruction repertoire. Generally p

C programming, At a shop of marbles, packs of marbles are prepared. Packets...

At a shop of marbles, packs of marbles are prepared. Packets are named A, B, C, D, E …….. All packets are kept in a VERTICAL SHELF in random order. Any numbers of packets with thes

What are the defining traits of an object-oriented language, The defining t...

The defining traits of an object-oriented language are: * Encapsulation * Inheritance * Polymorphism

Algorithm and pseudocodes, develop an algorithm using pseudocode for comput...

develop an algorithm using pseudocode for computing cos(x) and sin(x). use a sentinel controlled while loop. use the series definition of e^+-jx

Determine the block diagram of bcd adder, Determine the block diagram of bc...

Determine the block diagram of bcd adder To add 0110 to binary sum, we use a second 4-bit binary adder. The two decimal digits, together with input-carry, are first added in to

What is a message passing system, Distributed System 1. What is a messa...

Distributed System 1. What is a message passing system? Discuss the desirable features of a message passing system. 2. Discuss the implementation of RPC Mechanism in detail.

Determine the order in which optimized c-scan would service, Consider the s...

Consider the situation in which the disk read/write head is currently located at track 45 (of tracks 0-255) and moving in the positive direction. Assume that the following track re

Serialized when you perform serialization, What exactly is being serialized...

What exactly is being serialized when you perform serialization? Serialization is the process of changing an object into stream of bytes. We perform it at the time of transpor

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