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 an interrupt, Used to interrupt CPU normal implementation routine a...

Used to interrupt CPU normal implementation routine and to get its attention .Mostly generated by an external devices, timers, counters...etc

Explain about floating-executive model, Q. Explain about Floating-Executive...

Q. Explain about Floating-Executive model? Floating-Executive model: The master-slave kernel model is too restrictive in sense that only one of processors viz designated master

Mobile computing, Explain the key characteristics of mobile computing appli...

Explain the key characteristics of mobile computing applications

Write hit policies, Write Hit Policies: Write through o   Upd...

Write Hit Policies: Write through o   Update next level on every write o   Cache is always clean o   A lots of traffic to next level (mostly write) Write

Explain characteristics of program translation model, Explain characteristi...

Explain characteristics of program translation model. The program translation model characteristics are: A program should be translated before this can be executed.

Discuss about simple mail transfer protocol briefly, Discuss about Simple M...

Discuss about Simple Mail Transfer Protocol briefly. SMTP: It is sands for Simple Mail Transfer Protocol, is a protocol for sending e-mail messages among servers. Most e-

Dbms, sketch a neat E-R diagram for hotel management system with real time ...

sketch a neat E-R diagram for hotel management system with real time example

Enumerate about the specialised hardware, Enumerate about the Specialised h...

Enumerate about the Specialised hardware Specialised hardware such as protected memory or cryptographic memory module for storing and protecting the keys proves to be a good s

How will you prepare problem statement, How will you prepare problem statem...

How will you prepare problem statement? Problem statement should state what is to be completed and not how it is to be executed. It should be a statement of requirements not a

Illustrate about the single inheritance, Illustrate about the single inheri...

Illustrate about the single inheritance During inheritance, superclass feature may by override by a subclass defining that feature with the same name. The overriding features (

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