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

Program in java, Write a program to display grade message according to the ...

Write a program to display grade message according to the marks

Explain i/o buffer and advantage of buffering, What is an I/O buffer? What ...

What is an I/O buffer? What is the advantage of buffering? Is buffering always effective? Justify your answer with help of an example.   One type of I/O requirement arises from

Heuristic search strategies, Heuristic Search Strategies: Generally sp...

Heuristic Search Strategies: Generally speaking that, a heuristic search is one which have uses a rule of thumb to improve an agent's performance in solving the problems via s

Explain non-pre-emptive algorithms, Explain non-pre-emptive algorithms?   ...

Explain non-pre-emptive algorithms?   Non preemptive algorithms: In this algorithm a job is provided to CPU for execution as long as the job is non-completed the CPU cannot

Which TTL logic gate is used for wired anding, Which TTL logic gate is used...

Which TTL logic gate is used for wired ANDing ? Ans. Open collector output, TTL logic gate is used.

Running time - metrics for performance evaluation, Running Time - Metrics f...

Running Time - Metrics for performance evaluation: Running time is amount of time consumed in execution of an algorithm for a provided input on N-processor based parallel comp

Find out the excess code of decimal number, The excess 3 code of decimal nu...

The excess 3 code of decimal number 26 is ? Ans. (26) 10 in BCD is (00100110) BCD Add 011 to all BCD 01011001 for excess - 3

We declare a table control in the abap/4 program, How can we declare a tabl...

How can we declare a table control in the ABAP/4 program? Using the syntax controls type tableview using screen .

Role of internet, What are the roles of Internet, Intranet and extranet in ...

What are the roles of Internet, Intranet and extranet in e-business? Role of Internet, Intranet and extranet into e-business: The given information activities are carried

How to set a read or write watch point for a variable, By using Rwatch, Awa...

By using Rwatch, Awatch command in GDB we can set read or write watchpoint for a variable.

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