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

Give a simple example of dynamic modelling, Give a simple example of dynami...

Give a simple example of dynamic modelling using these notation A simple example using these notation is shown below in Figure:

State the concept of multiplicity, Multiplicity Multiplicity in an ass...

Multiplicity Multiplicity in an association specifies tells us about number of objects participate in a relationship. It decides the number of related objects. Multiplicity is

Explain user datagram protocol, Explain User Datagram Protocol. UDP(Use...

Explain User Datagram Protocol. UDP(User Datagram Protocol) : User Datagram Protocol uses a connectionless communication paradigm. It is an application using UDP does not re

Define the term- analysis, Define the term- Analysis The analysis invol...

Define the term- Analysis The analysis involves some or all of the following stages: Fact finding - this is usually done in four ways. Understanding the current syst

Polymorphism and inheritance in lingo programming, Question : (a) What...

Question : (a) What are parent scripts and child objects in Lingo object oriented programming (OOP)? What are the equivalent terms used in C++ OOP? (b) Differentiate b

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

Scope of expert system, The scope of the experts system is very limite...

The scope of the experts system is very limited. It cannot work outside the field it is being used. The users knowledge is required to adjust to new situation. To reduce

Define pipeline speedup, Define pipeline speedup. S(m)=T(l)/T(m) Whe...

Define pipeline speedup. S(m)=T(l)/T(m) Where T(m) is the execution time for some target workload on an m-stage pipeline. T(l) is the execution time for some workload an

How will these instructions perform?, Q. How will these instructions perfor...

Q. How will these instructions perform? Let's assume that above machine instructions are stored in three consecutive memory locations 1, 2 and 3 and PC contains a value (1) tha

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