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

Design a BCD to excess 3 code converter using NAND gates, Design a BCD to e...

Design a BCD to excess 3 code converter using minimum number of NAND gates. Hint: use k map techniques. Ans. Firstly we make the truth table: BCD no

Illustrate what is a ion pair energy, Q. Illustrate what is a ion pair ener...

Q. Illustrate what is a ion pair energy? Answer:- Ion energy contains electric charges called protons (+) and neutrons (0) and electrons (-) charges. It's present in an at

Prove using boolean algebra, Q.Prove using Boolean Algebra 1. X (X+Y) = ...

Q.Prove using Boolean Algebra 1. X (X+Y) = X 2. AB + AC + BC' = AC + BC' 3. (A+B+C) (A+B'+C') (A+B+C') (A+B'+C)=A 4. (A+B'+C) (AB+A'C) = (A+C) (A'+B) 5. XY + XZ + YZ

Difference among interrupt service routine and subroutine, Subroutine are t...

Subroutine are the part of implementing processes (like any process can call a subroutine for achieve task), whereas the interrupt subroutine never be the part. Interrupt subroutin

Explain assembly program execution, Q. Explain Assembly program execution? ...

Q. Explain Assembly program execution? An assembly program is written according to a strict set of rules. A word processor or editor is used for keying an assembly program in t

Why a function cannot call a task, Why a function can n ot call a task ...

Why a function can n ot call a task As functions doesn't consume time,it can do any operation which doesn't consume time. Mostly tasks are written that consumes time. So a ta

Why stored program control gains superiority over hard wired, In what way i...

In what way is stored program control superior to hard wired control? The SPC gains superiority over hard wired because of following points: SP C Ha

How to develop an object model, How to develop an object model To deve...

How to develop an object model To develop an object model firstly identify classes and their associations, as they affect overall problem structure and approach. Then prepare

Define categorization of parallel computers, Types Of Categorization Th...

Types Of Categorization The subsequent categorization of parallel computers has been identified: 1)  Categorization based on the instructions and data streams  2)  Catego

Example of pruning, Example of Pruning: As an example, we are assume t...

Example of Pruning: As an example, we are assume that the four choices for player one, there we are looking only two moves ahead 1 for player one and 1 for player two such as

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