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

By which transport protocol used, The transport protocol used by TFTP (Triv...

The transport protocol used by TFTP (Trivial File Transfer Protocol) is? The transport protocol used through Trivial File Transfer Protocol is UDP.

Determine why a new system is required, Q. Determine why a new system is re...

Q. Determine why a new system is required? Feasibility Study: - Feasibility study is the method of defining the current problem determining why a new system is essential and

Analog to digital convertor, In which A/D converter has the speed of conver...

In which A/D converter has the speed of conversion is maximum ? Ans. In Parallel-comparator A/D converter, the speed of conversion is maximum. Speed of conversion is maximum a

Greedy search - artificial intelligence, Greedy Search - artificial intelli...

Greedy Search - artificial intelligence: If we have a heuristic function for states, defined as above, so we can simply measure each state with respect to this measure and ord

While using ftp what is wildcard expansion in file names, While using FTP w...

While using FTP what is wildcard expansion in file names? To make this easy for users to identify a set of file names, FTP permits a remote computer system to perform usual fil

How can a shift register be used as a counter, What is a shift register? Ca...

What is a shift register? Can a shift register be used as a counter? If yes, explain how?     Ans: Shift Register: A register wherein data gets shifted towards left or right

What is fork, What is Fork Clk gets its value after 1 time unit, rese...

What is Fork Clk gets its value after 1 time unit, reset after 10 time units, enable after 5 time units, data after 3 time units. All the statements are executed in parallel.

How linq is beneficial than stored procedures, There are couple of benefit ...

There are couple of benefit of LINQ over stored procedures.   1. Debugging - It is really very difficult to debug the Stored procedure but as LINQ is part of .NET, you can us

How to use data validation function in vba, Data validation is a significan...

Data validation is a significant concept in VBA. Application process and a custom dialog box can be used to accurate input errors. You can assign an application process to the fram

What search method would be most appropriate and why, (a) Describe fully in...

(a) Describe fully in your own words the following terms: (i) Turing Test (ii) Agent (iii) Utility-based agent (b) A Mars rover has to leave the lander, collect rock sample

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