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

Micro programmed control and hardwired control, Explain micro programmed co...

Explain micro programmed control. Ans: A micro programmed control unit is made around storage till is called a control store where all the control signals are stored in a prog

Explain creating files for writing only in c, Creating Files for Writing On...

Creating Files for Writing Only Creating Files for Writing Only : To create a text file for writing only, pass "w" into fopen as the second argument. This example follows along

What is digital versatile disk, Digital versatile disk (DVD) This is an...

Digital versatile disk (DVD) This is an optical system for storing data. It's similar to CD though typically can hold 4.7 Gbyte of data compared to only 700 MB of data on a CD.

Determine the gray code for decimal number, Determine the equivalent Gr...

Determine the equivalent Gray code for decimal number 6 ? Ans. The equivalent Gray code for decimal number 6 is 0101 Because the Decimal number 6 is equivalent to binary nu

What is assembler, Q. What is Assembler? An assembly program is used to...

Q. What is Assembler? An assembly program is used to transfer assembly language mnemonics to binary code for every instruction after the complete program has been written with

Explain the concept of generalization, Explain the concept of Generalizatio...

Explain the concept of Generalization Generalization and inheritance are powerful abstractions for sharing the structure and/or behaviour of more than one class.  Generalizati

Function of host to host transport layer in tcp/ip protocol, Illustrate the...

Illustrate the function of host to host transport layer in TCP/IP protocol stack? Function of Host - to-Host Transport Layer: This protocol layer just above inter network

Very long instruction word architecture, Superscalar architecture was desig...

Superscalar architecture was designed to increase the speed of the scalar processor. But it has been realized it's not easy to apply. Subsequent are a number of problems faced in t

Explain call completion rate in telephone traffic, With reference to teleph...

With reference to telephone traffic, explain the terms CCR. CCR: Call completion rate is explained as the ratio of the number of successful calls to the number of call attemp

Describe big notation, Q. Describe Big Notation? Big O Notation : The ...

Q. Describe Big Notation? Big O Notation : The set O (g(n)) comprises all functions f(n) for that there exists   positive constants c such that for satisfactorily large values

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