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 is page frame, What is page frame? An area in the main memory that...

What is page frame? An area in the main memory that can hold single page is called as page frame.

Illustrate the examples of simulations, Illustrate the Examples of simulati...

Illustrate the Examples of simulations -  Training (for example pilots, drivers, etc.) -  Running/testing nuclear plants and chemical plants -  trying out equipment to be

Explain about heterogeneous linked list, If you are using C language to imp...

If you are using C language to implement the heterogeneous linked list, what pointer type will you use? The heterogeneous linked list having different data types in its nodes a

Decision Tree - ID3 algorithm:, . weather (windy, rainy or sunny) 2. how...

. weather (windy, rainy or sunny) 2. how much money you have (rich or poor) 3. whether your parents are visiting (yes or no)

State the disadvantages of interviewing, State the Disadvantages of  inter...

State the Disadvantages of  interviewing -  can be expensive to carry out    -  can be a very time consuming exercise -  Unable to remain anonymous

8086, the block diagram of an 8086 processor

the block diagram of an 8086 processor

What is the main problem with segmentation, What is the main problem with s...

What is the main problem with segmentation? Problem with segmentation (i) Is with paging, such mapping needs two memory references per logical address that slows down the

Two properties of recursion, Two properties of recursion are:- 1. A sm...

Two properties of recursion are:- 1. A smallest, base case that is processed without recursion and acts as decision criterion for stopping the method of computation and 2.

Which is most general phase structured grammar, Which is most general phase...

Which is most general phase structured grammar? Context – Sensitive is most common phase structured grammar.

Name the numerous household devices, Name the Numerous household devices ...

Name the Numerous household devices Numerous household devices now use microprocessors to control their different functions. The following is just a sample of common devices (d

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