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

Resolution method - artificial intelligence, Resolution Method - Artificial...

Resolution Method - Artificial intelligence: A minor miracle happened in 1965 when Alan Robinson published his resolution function. This function uses a generalized format of t

Assembler directives, What are assembler directives? Ans: These are th...

What are assembler directives? Ans: These are the instructions that direct the program to be executed. They have no binary corresponding so they are called pseudo-opcodes. The

Explain about semiconductor memories, Q. Explain about Semiconductor Memori...

Q. Explain about Semiconductor Memories? Originally IC technology was used for constructing processor however soon it was realized that same technology can be used for construc

Explain about hybrid model, Q. Explain about Hybrid model? Hybrid model...

Q. Explain about Hybrid model? Hybrid models are normally tailor-made models suiting to particular applications. In fact these fall in category of mixed models. These type of a

Decision trees, Decision Trees: Visualize you only ever do four things...

Decision Trees: Visualize you only ever do four things at the weekend such as go shopping or watch a movie or play tennis and just stay in. In such case what you do depends on

Excess 3 codes, Explain Excess 3 Codes Ans. Excess 3 Codes 1....

Explain Excess 3 Codes Ans. Excess 3 Codes 1. This is the other form of BCD code. All decimal digits are coded in 4 bit binary code. 2. The code for all decimal di

Explain direct broadcast & limited broadcast, Explain Direct broadcast & li...

Explain Direct broadcast & limited broadcast. Broadcast is a method to send a packet to all the stat ions on an exact network at once. Broadcast systems permit the possibility

Determine about the logical shift, Logical shift A logical shift operat...

Logical shift A logical shift operation transfers 0 through serial input. We apply symbols shl and shr for logical shift left and shift right microoperations, examples:. R1

What is dot pitch of a CRT, Q. What is Dot Pitch of a CRT? Dot Pitch of...

Q. What is Dot Pitch of a CRT? Dot Pitch of a CRT is the distance between phosphor dots of same colour. In Trinitron screens, the term Slot Pitch is used in place of Dot Pitch

Define a segment index or an internal index, The field that contains a segm...

The field that contains a segment index or an internal index is called ? Ans. Target datum consists of a segment index or an internal index.

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