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

.., consider an open circuit pn junction.sketch curves as a function of dis...

consider an open circuit pn junction.sketch curves as a function of distance across the junction of space charge ,electric field and potential

Define a register, Define a register. Ans:  Register:   A register...

Define a register. Ans:  Register:   A register contain a group of flip-flops and gates which effect their transition. The flip flops hold the binary information and the g

Basic working of semiconductors, Q. Basic working of Semiconductors? Se...

Q. Basic working of Semiconductors? Semiconductors are crystalline solid materials whose resistivities have values between those of conductors and insulators. Conductivity rang

Master scheduling , The alpha beta company generates two products; A and B,...

The alpha beta company generates two products; A and B, that are made from components C and D. Given the following product structures, master scheduling requirements and inventory

Explain about indexed addressing scheme, In this technique, operand field o...

In this technique, operand field of instruction includes an address and an index register thatcomprises an offset. This addressing scheme is normally used to address the consecutiv

Desirable characteristics of an electronic market place, What are the desir...

What are the desirable characteristics of an Electronic Market Place?  Characteristics of an Electronic Market Place:  a. Its electronic, the business center is not a phys

Two services that are used to deal with communication, Explain about the tw...

Explain about the two services that are used to deal with communication. Message Service: Used by the application servers to change short internal messages, all system commu

What is an arithmetic processor, Q. What is an arithmetic processor? A ...

Q. What is an arithmetic processor? A distinctive CPU necessitates most of the control and data processing hardware for implementing non-arithmetic functions. As the hardware c

Bus arbitration - computer architecture, Bus arbitration: In single bu...

Bus arbitration: In single bus architecture when more than 1 device requests the bus, a controller known as bus arbiter decides who gets the bus; this is known as the bus arbi

Difference between next and continue clause, The difference among the next ...

The difference among the next and continue verb is that in the continue verb it is used for a situation where there is no EOF condition that is the records are to be accessed again

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