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

Define structural classification, Structural Classification Flynn's cla...

Structural Classification Flynn's classification explains the behavioural idea and doesn't take concern into the computer's structure. Parallel computers can be categorized bas

#dbms., #example of cascading rollback#

#example of cascading rollback#

Define nondeterministic tm, Define nondeterministic TM?  Arbitraril...

Define nondeterministic TM?  Arbitrarily chooses move when more than one possibility exists Accepts if there is at least one computation that terminates in an acceptin

Explain the input stage of an ADC, Explain the Input Stage of an ADC. ...

Explain the Input Stage of an ADC. Ans. Input Stage- In ADC at the input stage, analog voltage can contain any value in a range although the digital output can contain

Assembler directives, Assembler directives: An assembler directive is ...

Assembler directives: An assembler directive is a statement to give direction to the assembler to perform the task of assembly process. Assembler directives control organizati

Define pipeline speedup, Define pipeline speedup. S(m)=T(l)/T(m) Whe...

Define pipeline speedup. S(m)=T(l)/T(m) Where T(m) is the execution time for some target workload on an m-stage pipeline. T(l) is the execution time for some workload an

Limitation identified in amdahls law, Q. Limitation identified in Amdahls l...

Q. Limitation identified in Amdahls law? There is one main limitation identified in Amdahl's law. As said by Amdahl's law workload or problem size is forever fixed as well as n

How can you have an accession number, Accession number (bioinformatics), a ...

Accession number (bioinformatics), a unique identifier given to a biological polymer sequence (DNA, protein) when it is given to a sequence database.

Flynns categorization, Normal 0 false false false EN-US...

Normal 0 false false false EN-US X-NONE X-NONE

What is a map, What is a Map? A Map is an Array, which having the addre...

What is a Map? A Map is an Array, which having the addresses of the free space in the swap device that are allocatable resources, and the number of the resource units available

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