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

Rational schema, write the rational schema and draw it’s dependency diagram...

write the rational schema and draw it’s dependency diagram. Identify all dependencies.

ip address and port number at the remote host, How many TCP connections ar...

How many TCP connections are in the "Established" state? Contain relevant output. For one of the established TCP connections, what are the IP address and port number at the remote

Explain what the difference between the two readings, The following sentenc...

The following sentences have a (potential) scope ambiguity. Give two translations into predicate logic for each sentence (one formula for each reading), and explain in words what t

Cookies, basic purpose of cookies

basic purpose of cookies

Illustrate the purchase consummation activity, Illustrate the Purchase Cons...

Illustrate the Purchase Consummation activity? Purchase Consummation: This model lists three activities in the purchase consummation phase: • Receipt of product. • Pl

Send a report to the printer, How to send a report to the printer instead o...

How to send a report to the printer instead of displaying it on the screen? We can send a report to the printer instead of displaying it on the screen.  To do this, use the key

The events of an aspx page execute, In what order do the events of an ASPX ...

In what order do the events of an ASPX page execute. As a developer is it important to understand these events?   If you try to access it in Page_Load that is way previous th

Illustrate associative memory, Q. Illustrate Associative Memory? The ti...

Q. Illustrate Associative Memory? The time required to find an item which is stored in memory can be decreased significantly if stored data can be identified for access by cont

Student, Suppose we have an array-based list A[0..N - 1] and we want to del...

Suppose we have an array-based list A[0..N - 1] and we want to delete all duplicates. LastPosition is initially N - 1, but gets smaller as elements are deleted. Consider the pseudo

Big – endian and little- endian representations, Explain Big - Endian and L...

Explain Big - Endian and Little- Endian representations Ans: The Big- endian is used where lower byte addresses are used for the more significant bytes (leftmost bytes) of 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