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

What are difference between mealy and moore state machine, What are differe...

What are difference between Mealy and Moore state machine? Difference between Mealy and Moore state machine: 1) Mealy and Moore models are the fundamental models of state ma

Application and factors related to scanners, Q. Application and factors rel...

Q. Application and factors related to Scanners? When you purchase a scanner there are various factors which can be looked at: Compatibility of Scanner with your Computer, The T

Implementation using 8 to 1 multiplexer, Implement the following function u...

Implement the following function using 8 to 1 multiplexer Y(A, B, C, D) = ∑(0,1,2,5,9,11,13,15) Ans. We will obtain three variables B,C and D at selection lines and also A as i

Explain passing parameters using pointers, Q. Explain Passing Parameters Us...

Q. Explain Passing Parameters Using Pointers ? This method overcomes the drawback of using variable names directly in procedure. It uses registers to pass procedure pointers to

What is a unix device driver, A UNIX device driver is ? Ans. A UNIX devi...

A UNIX device driver is ? Ans. A UNIX device driver is structured in two halves termed as top half and bottom half.

Bidirectional search, Bidirectional Search: We've concentrated so far ...

Bidirectional Search: We've concentrated so far on the searches where the point of view for the search is to find a solution, but not the path to the solution. Like any other

Commutativity of connectives, Commutativity of Connectives : In this y...

Commutativity of Connectives : In this you will be aware of the fact that some arithmetic operators that have a property which it doesn't matter that way around you give the o

What are the properties of e-cash, What are the properties of E-cash? ...

What are the properties of E-cash? Properties: a. Monetary Value: It must be backed through either cash, bank –certified cashier’s cheque and authorized credit cards.

What is cgi, CGI stands for Common Gateway Interface, and is a mechanism by...

CGI stands for Common Gateway Interface, and is a mechanism by which a browser is permitted to communicate with programs running on a server. If you look at every word in turn it m

What is double data rate sdram, What is double data rate SDRAM?  Double...

What is double data rate SDRAM?  Double data rates SDRAM are those which can transfer data on both edges of the clock and their bandwidth is fundamentally doubled for long burs

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