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 measures to be taken in the design, What are the measures or p...

What are the measures or precautions to be taken in the Design when the chip has both analog and digital portions? As today's IC has analog components also inbuilt, some design

Enumerate about the decimal arithmetic unit, Enumerate about the Decimal Ar...

Enumerate about the Decimal Arithmetic Unit The user of the computer input data in decimal numbers and receives output in the decimal form. But a CPU with ALU can perform arith

Name the two operations of stack, Name the two operations of stack A st...

Name the two operations of stack A stack has only two operations and they are insertion and deletion of items. The operation insertion is called push (or push-down) as it can b

Hrm, hrm digrams

hrm digrams

How many select lines will a 32:1 multiplexer will have, How many select li...

How many select lines will a 32:1 multiplexer will have ? Ans. 5 select lines will be required for 32 inputs, as 2 5 = 32.

How to use activex control in .net, How to use ActiveX Control in .Net ? ...

How to use ActiveX Control in .Net ? ActiveX control is a special type of COM component that handles a User Interface. Using ActiveX Control in your .Net Project is even simple

What is big endian and little endian format, What is big endian and little ...

What is big endian and little endian format? The name big endian is used when lower byte addresses are used for the more important of the word. The name little endian is used f

What is a semaphore, What is a semaphore? Semaphore: It is a protecte...

What is a semaphore? Semaphore: It is a protected variable or abstract data type that constitutes the typical method for restricting access to shared resources as shared memo

Does xml replace html, No XML does not replace HTML. Instead, it gives an a...

No XML does not replace HTML. Instead, it gives an alternative which permits you to explain your own set of markup elements. HTML is expected to stay in common use for some time to

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