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 advantages and disadvantages of a active document, Explain advantag...

Explain advantages and disadvantages of a active document. The advantage of an active document over a dynamic document lies in its capability to update the information contin

Define the meaning of business-to-business, Define the meaning of business-...

Define the meaning of business-to-business. B2B (business-to-business): The consensus is universal: it is the priority; it is where the money is. It’s rather true; theref

What is the vertical organizational structure, What is the Vertical Organiz...

What is the Vertical Organizational Structure? This is a traditional approach that is typified by a functional approach to work in that departments work onto tasks relevant to

In which page replacement policies balady’s anomaly occurs, In which page r...

In which page replacement policies Balady’s anomaly occurs? FIFO that is First in First Out.

Engineering and scientific software, Engineering and Scientific Software ...

Engineering and Scientific Software Engineering  and  Scientific  software  has  been  characterized  with "number crunching" algorithms. Application starts from astronomy t

Delete a user from a category, Execute the following functionality using Ja...

Execute the following functionality using Java & SQL with simple GUI interface: 1.  Insert/delete/update an XML document.  2.  Insert/delete/update a category.  3.  Alloca

Cloud computing assignment, In the module on WSDL you were presented with t...

In the module on WSDL you were presented with the details of the WSDL service that receives a request for a stock market quote and returns the quote. The basic structure of a WSDL

Define file record length, Define File record length ? File record leng...

Define File record length ? File record length must be selected to match the data characteristics.

Capacity and access speed of hard disk, Capacity and access speed: PC ...

Capacity and access speed: PC hard disk drive capacity (measured in GB). The vertical axis is logarithmic, so the accurate line corresponds to exponential growth.  By using

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