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

Processes of information system, Processes of Information System The b...

Processes of Information System The basic purpose of the Information System is to convert and manage data into something that is meaningful. Bocij et al (2003) lists the basic

How address resolution is performed with table lookup, How address resoluti...

How address resolution is performed with table lookup? Explain with the help of a suitable example. The approach of table lookup to address resolution needs a data structure wh

Define com programs, Q. Define COM Programs? A COM (Command) program is...

Q. Define COM Programs? A COM (Command) program is binary image of a machine language program. It is loaded in memory at the lowest available segment address. Program code star

Perform subtraction in base 5 using r and r-1 complement, Q Write a menu dr...

Q Write a menu driven program to perform subtraction in base 5 using r and (r-1) complement with necessary validations.

What is a piconet in a bluetooth context, Problem: (a) IEEE802.11 supp...

Problem: (a) IEEE802.11 supports two types of network architecture, describe these architectures with the support of diagrams detailing the network components. (b) The MAC

What is sgml, SGML is very large, influential, and difficult. It has been i...

SGML is very large, influential, and difficult. It has been in important industrial and commercial use for nearly two decades, and there is a important body of expertise and softwa

Expert systems, An expert systems is software that contains a knowledge ...

An expert systems is software that contains a knowledge base of facts and relationships and has the ability to make inferences based on that knowledge base. An experts sys

Define race condition, Define race condition.  When several process acc...

Define race condition.  When several process access and manipulate similar data concurrently, then the outcome of the implementation depends on particular order in which the ac

Basic computer, The use of Information Technology (IT) is well known. IT ha...

The use of Information Technology (IT) is well known. IT has turn into a must for survival of all business houses with growing information technology trends. Computer is main compo

Show data representation for computation, Binary codes exist for any fundam...

Binary codes exist for any fundamental representation. Binary codes can be created for any set of discrete elements for example colors, spectrum, musical notes, chessboard position

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