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 are the layers of data description in r/3, What are the layers of data...

What are the layers of data description in R/3? There layesr are there:- The external layer. The ABAP/4 layer. The database layer.

Inheritance, Create a new project, LastNameFirst 05, for this assignment. ...

Create a new project, LastNameFirst 05, for this assignment. You will need to define the classes depicted in the class diagram below. All of the classes should contain complete ja

Vertical alignment of fields one below the other, Which Command permits for...

Which Command permits for vertical alignment of fields one below the other. UNDER Command is used ofr vertical alignment.

What is block scope, What is Block scope Block scope: The variables w...

What is Block scope Block scope: The variables with block scope appear in a block or within the list of formal parameter declarations in a function definition. It is visible

Briefly explain the floating point representation, Briefly explain the floa...

Briefly explain the floating point representation with an example? The floating point representation has 3 fields 1.sign bit 2.siginificant bits 3.exponent For  exa

Explain types of assembly programs, Q. Explain types of assembly programs? ...

Q. Explain types of assembly programs? Assembly language programs can be written in two manners: COM Program: Having all segments as part of one segment EXE Program: that hav

Distinguish between how ntfs and fat store time, Problem (a) Distingu...

Problem (a) Distinguish between how NTFS and FAT store time. Describe your answer. (b) Unix epoch starts as from January 1, 1970, 00:00:00 GMT. Provide that Unix stores

Internal conditioning, types of internal conditioning with explanations and...

types of internal conditioning with explanations and examples

How is a multidimensional array defined pointer, How is a multidimensional ...

How is a multidimensional array defined in terms of a pointer to a collection of contiguous arrays of lower dimensionality ? C does not have true multidimensional arrays. Howev

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