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 are the reasons behind using intranet, Reason behind using Intranet ...

Reason behind using Intranet The major reasons for doing this include: -  Safer as there is less chance of external viruses or hacking -  It's possible to prevent employe

Name a different return types of a controller action method, The following...

The following are just a few return types of a controller action process. In common an action process can return an instance of an any class that derives from Action Result class.

Security features used in client-server types of network, Security features...

Security features used in Client-Server types of network are as follows :  i) Digital Signatures ii)  Encryption / Decryption iii) Secure Socket Layer (SSL) iv) Firewa

Differentiate between the message and method in c++, Message in C++ : *...

Message in C++ : * Objects converse by sending messages to each other. * A message is sent to invoke a method in C++.   Method in C++: * Gives response to a message

What is the system call available to change the personality, What is the sy...

What is the system call available to change the personality? The system call personality prefers to a method to modify its implementation domain in order that Linux can emulate

-bit comparator using combinational logic, Design a 4-bit comparator using ...

Design a 4-bit comparator using combinational logic, and Karnaugh Maps. The inputs of the circuit are two 2-bit numbers. a) Construct the truth table given 2-bits inputs A and B, a

What is managed bean or mbean, A managed bean - sometimes simply referred t...

A managed bean - sometimes simply referred to as an MBean - is a type of JavaBean, developed with dependency injection. Managed Beans are particularly used in the Java Management E

How do we synthesize verilog into gates with synopsys, How do we synthesize...

How do we synthesize Verilog into gates with Synopsys?  The answer can, of course, occupy various lifetimes to completely answer.. BUT.. a straight-forward Verilog module can b

Explian two limitations of dead-box analysis, (a) Explian two limitations o...

(a) Explian two limitations of dead-box analysis. (b) Describe why memory analysis is difficult. (c) With reference to the "Shadow Walker" rootkit, explain what is meant by

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