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

What is generalization, What is generalization? Generalization is a rel...

What is generalization? Generalization is a relationship among a class (super class) and one or more variations of the class (sub classes).It arrange classes by similarities an

What is swapping, What is swapping?   A process can be swapped out tempo...

What is swapping?   A process can be swapped out temporarily of memory to a backing store and after that brought back in memory for execution as continued.

The values 15 and 11 can also be defined by variable, In the statement Writ...

In the statement Write:/15(10) lfa1-lifnr. The values 15 and 11 can also be defined by variable. No, the value of 11 nad 15 is not described by variable.

What is the benefit of report wizard over an auto report, What is the benef...

What is the benefit of Report Wizard over an Auto Report? It takes a little more work to make a report with the report wizard than with the Auto Report but you have a lot more

Sort Wars, If quicksort is so quick, why bother with anything else? If bubb...

If quicksort is so quick, why bother with anything else? If bubble sort is so bad, why even mention it? For that matter, why are there so many sorting algorithms?

What is visibility give uml notation, What is visibility give UML notation?...

What is visibility give UML notation? Visibility refers to the ability of a process to reference a feature from another class and has possible valued of public, private, protec

What is hard drive interface, Q. What is Hard Drive Interface? Secondar...

Q. What is Hard Drive Interface? Secondary storage devices need a controller to proceed as an intermediary between device and rest of the computer system. On some computers the

Explain the accuracy of an ADC, Explain the Accuracy o f an ADC. Ans...

Explain the Accuracy o f an ADC. Ans Accuracy- The accuracy of D to A converter is the difference among actual output voltage and the expected output voltage in D to A c

What is a crosstab query wizard, What is a crosstab query wizard? A wiz...

What is a crosstab query wizard? A wizard that helps us to show the data in a two-dimensional tabular format is the crosstab query wizard. You can use this to make queries that

Full resolution rule - artificial intelligence, Full Resolution Rule - Arti...

Full Resolution Rule - Artificial intelligence: Now that we know about unification, we can correctly describe the complete edition of resolution: p1  ∨ ...  ∨ pj  ∨ ...  ∨ p

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