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

Setjmp and longjmp, How does throwing and catching exceptions differ from u...

How does throwing and catching exceptions differ from using setjmp and longjmp? Ans) The throw operation calls the destructors for automatic objects instantiated as entry to th

What is hamiltonian path, What is Hamiltonian path?  A Hamiltonian path...

What is Hamiltonian path?  A Hamiltonian path in a directed graph G is a directed path that goes through every node exactly once. We consider a special case of this problem whe

Can you tell me some of system tasks and their purpose, Can you tell me som...

Can you tell me some of system tasks and their purpose? $display, $displayb, $displayh, $displayo, $write, $writeb, $writeh, $writeo. The most useful of these is $display. T

Demultiplexers, Explain briefly about demultiplexers?

Explain briefly about demultiplexers?

Explain advantage of static storage class, Explain advantage of static stor...

Explain advantage of static storage class The second and more subtle use of 'static' is in connection with external declarations. With external constructs it provides a privacy

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

Layout for the assumed penalty, Solve the following 8-department problem us...

Solve the following 8-department problem using the MIP method.  What is the resulting layout and flow-distance score?  Note that the aspect ratio of each department should be 2.

Functionality of hyper thread processor, Hyper-threading works by duplicati...

Hyper-threading works by duplicating those sections of processor that kept the architectural state-but not duplicates the main implementation resources. This allows a Hyper-threadi

Differentiate between static and dynamic step loops, Differentiate between ...

Differentiate between static and dynamic step loops. Step loops fall into two classes: Static and Dynamic.  Static step loops have a fixed size that cannot be changed at runti

What is missing offset, Q. What is Missing offset? The xxxx in machine ...

Q. What is Missing offset? The xxxx in machine language for instruction at line 0010 is there since the assembler doesn't know DATA segment location which will be determined at

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