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

Write a short note on pointer operators in c, Write a short note on pointer...

Write a short note on pointer operators in c Pointers (that is, pointer values) are generated with the ''address-of'' operator &, which we can also think of as the ''pointer-to

What is structural hazard, What is structural hazard? Structural hazard...

What is structural hazard? Structural hazard is the situation when two instructions needs the use of a given hardware resource at the similar time. The most common case in whic

What are the various address translation schemes, What are the various addr...

What are the various address Translation schemes? Explain which scheme is used in Internet? Translation from a computer's protocol address to a corresponding hardware address i

Define mfc, Define MFC. To accommodate the variability in response time...

Define MFC. To accommodate the variability in response time, the processor waits unless it receives an indication that the requested read operation has been done. The control s

What is the disadvantage of strobe method, What is the  disadvantage of st...

What is the  disadvantage of strobe  method. The drawbacks of strobe method are that the source unit that show the transfer has no way of knowing whether the destination unit h

Benefits of having densely packed integrated circuits, What are benefits of...

What are benefits of having densely packed Integrated Circuits? These are stated below: Reliability: The integrated circuit interconnections are in fact more reliable

What are common reason for error massages while copying file, Q. What are c...

Q. What are common reason for error massages while copying file? While copying files with copy, DOS in encounters any error, it displays a suitable error massage. The common re

Define memory read and write operation, Define Memory read and write operat...

Define Memory read and write operation The transfer of information from a memory word to outside environment is known as read operation. The transfer of new information to be k

What is tri-state logic, Three Logic Levels are used and they are High, Low...

Three Logic Levels are used and they are High, Low, High impedance state. The high and low are normal logic levels & high impedance state is electrical open circuit conditions. Tri

Order in which filters get implemented, If we have multiple filters implet...

If we have multiple filters impleted, what is the order in which these filters get implemented?   Ans) 1. Authorization filters 2. Response filters 3. Action filters

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