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

Explain vector-memory instructions, Vector-Memory Instructions When vec...

Vector-Memory Instructions When vector operations with memory M are carried out then these are vector-memory instructions. These instructions are referred with the subsequent f

How will these instructions perform?, Q. How will these instructions perfor...

Q. How will these instructions perform? Let's assume that above machine instructions are stored in three consecutive memory locations 1, 2 and 3 and PC contains a value (1) tha

Vliw instruction word, VLIW instruction word is compacted to have floating-...

VLIW instruction word is compacted to have floating-point addition, one branch, floating point multiply, and one integer arithmetic and load/store operation as displayed in Figure

By which except ions of type error in java are handled, Except ions of type...

Except ions of type error in JAVA are handled by? Except ions of type error in the JAVA are handled through JAVA run time environment.

Explain design of adder, Q. Explain Design of adder? Adders play one of...

Q. Explain Design of adder? Adders play one of the most significant roles in binary arithmetic. As a matter of fact fixed point addition is frequently used as a simple measure

What are the four linq providers that .net framework ships, 1. LINQ to Obje...

1. LINQ to Objects - Implements a LINQ query against a collection of objects 2. LINQ to XML - Implements an XPATH query against XML documents 3. LINQ to SQL - Implements LINQ

Explain the differences of casex and casez, Explain the differences of case...

Explain the differences of casex and casez over the case statement? casex operator has to be used when both high impedance value (z) and unknown (x) in any bit  has  to  be  t

Define restoring method, Define restoring method? The hardware method j...

Define restoring method? The hardware method just explained is called the restoring method. The reason for this name is that the partial reminder is restored by adding the divi

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