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

Stack operation and interrupts in microprocessor, Let us review the operati...

Let us review the operation of the stack within the 68HC11, the stack is a defined area of RAM which is last in first out register (LIFO) . Access to the stack is made via a stack

What is dynamic memory allocation, What is dynamic memory allocation? T...

What is dynamic memory allocation? The mechanism of allocating needs amount of memory at run time is known as dynamic allocation of memory. Sometimes it is needed to allocate m

What are two methods of modifying sap standard tables, What are two methods...

What are two methods of modifying SAP standard tables? Append Structures and Customizing Includes.

What are the defining traits of an object-oriented language, The defining t...

The defining traits of an object-oriented language are: * Encapsulation * Inheritance * Polymorphism

Explain cache organisation, Q. Explain Cache Organisation? Cache memori...

Q. Explain Cache Organisation? Cache memories are found in nearly all latest computers.  They are very helpful for increasing speed of access of information from memory.  Let's

Explain frequency-division multiplexing, Q. Explain Frequency-division mult...

Q. Explain Frequency-division multiplexing? Frequency-division multiplexing (FDM) is a technique for data transmission widely used in telephone, radio, and cable TV systems in

Doubly linked list than by singly linked list, Which operations is performe...

Which operations is performed more efficiently by doubly linked list than by singly linked list Deleting a node whose location is given.

Control signal, justify whether the control signal passes through same bus ...

justify whether the control signal passes through same bus as data ,address and instruction or not?

Role of internet, Role of Internet, Intranet and extranet in e-business ...

Role of Internet, Intranet and extranet in e-business The following information activities are carried out in many business: 1.  Selling of raw materials 2.  Advertising o

Explain is cgi a script or a program, The distinction is semantic. Traditio...

The distinction is semantic. Traditionally, compiled executables (binaries) are known as programs, and interpreted programs are usually known as scripts. In the context of CGI, the

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