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

Disadvantages of stateful multi-layer inspection, Disadvantages of Stateful...

Disadvantages of Stateful Multi-Layer Inspection A firewall such as the SMLI remains completely transparent to both users and applications. Consequently, SMLI firewall does no

Discuss briefly subscriber loop system, Discuss briefly subscriber loop sys...

Discuss briefly subscriber loop system. Subscriber Loop System: Every subscriber in a telephone network is connected usually to the nearest switching office using a dedicated

Credit line, The Credit Line The Credit Line is a set of informational f...

The Credit Line The Credit Line is a set of informational facts usually found below or beside a picture of a work of art. Should the picture appear in a book, magazine, poster,

Path & Path Production, Take the following flow graph and use the procedure...

Take the following flow graph and use the procedure in chapter 8 to derive an equivalent regular expression. Show all intermediate graphs (to ensure that you follow the procedure,

Artificial intelligence agents, Artificial Intelligence Agents: We int...

Artificial Intelligence Agents: We introduced what we'll be conversation about in Artificial Intelligence and why those things are necessary. This discussion is of course abou

Give difference between top down and bottom up parsing, Give difference bet...

Give difference between top down parsing and bottom up parsing. Top down parsing: Specified an input string, top down parsing tries to derive a string identical to this by s

What are the roll and page areas, What are the roll and page areas? Ro...

What are the roll and page areas? Roll and page areas are SAP R/3 buffers used to kept user contexts (process requests).  The SAP dispatcher assigns procedure requests to work

What are the different types of bios, The  most common types are the AWARD,...

The  most common types are the AWARD,AMI, AND phoenix

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