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 about the microsoft and the netscape, Explain about the Microsoft a...

Explain about the Microsoft and the Netscape With the increasing competition between certain vendors especially the Microsoft and the Netscape, there have been a number of chan

Explain the race condition, Explain the Race Condition The situation wh...

Explain the Race Condition The situation where various processes access - and manipulate shared data concurrently. The final value of the shared data relies upon which process

Implement a memory management system , There should be 1 server thread and ...

There should be 1 server thread and N client threads, where N is supplied by the user as a command line argument. The server opens a file called "all_requests.dat", the file has

Task information displays in search-based tools, Q. Task Information Displa...

Q. Task Information Displays in Search-based tools? Task Information Displays principally give visualization of different locations in parallel program where bottlenecks have o

Which device converts BCD to seven segment, A device which converts BCD to ...

A device which converts BCD to Seven Segment is called ? Ans. DECODER is a device that converts BCD to Seven Segment. This coverts binary words in alphanumeric characters.

What is a sparse matrix, What is a sparse matrix? Sparse Matrix A m...

What is a sparse matrix? Sparse Matrix A matrix in which number of zero entries is much higher than the number of non-zero entries is known as sparse matrix. The natural me

Explain clr, What is CLR?  CLR(Common Language Runtime) is the major r...

What is CLR?  CLR(Common Language Runtime) is the major resource of .Net Framework. It is collection of services like garbage collector, exception handler, jit compilers etc. w

Explain the probability of availability of free lines, How does one arrive ...

How does one arrive at the probability of availability of free lines during the busy hour? One can arrive at the possibility of free lines throughout busy hour using the delay

By which digits are represented, In a DTMF phone, digits are represented by...

In a DTMF phone, digits are represented by: (A)  Orthogonal frequencies. (B)  Orthogonal Phases. (C)  Orthogonal codes. (D)  Orthogonal pulses. Ans: Di

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