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

The spanning tree of connected graph with 10 vertices, The spanning tree of...

The spanning tree of connected graph with 10 vertices have 9 edges of spanning tree of connected graph with 10 vertices

What is downcasting in programming, Downcasting concept is the casting from...

Downcasting concept is the casting from a general to a more particular type, i.e. casting down the hierarchy in programming

Show various RISC processors, Q. Show Various RISC Processors? RISC has...

Q. Show Various RISC Processors? RISC has fewer design bugs and its simple instructions decrease design time. Sodue to all the above important reasons RISC processors have beco

Diffrentiate between non-relocatable & relocatable programs, How non-reloca...

How non-relocatable programs are different from relocatable programs? Non relocatable program: It is one that cannot be made to execute in any type of area of storage other t

Can a vector have a component equivalent to zero, Q. Can a vector have a co...

Q. Can a vector have a component equivalent to zero and still have a nonzero magnitude? Answer:- Yes For example the 2-dimensional vector (1, 0) has length sqrt (1+0) = 1

What is the mips assembly code, Question: (a) Using an appropriate dia...

Question: (a) Using an appropriate diagram, illustrate the structure of an instruction used for branching purposes and state the purpose of each part. (b) Given the number

What is a table pool, What is a table pool? A table pool (or pool) is ...

What is a table pool? A table pool (or pool) is used to join several logical tables in the ABAP/4 Dictionary.  The definition of a pool having of at least two key fields and a

Explain register addressing mode, Q. Explain Register Addressing Mode? ...

Q. Explain Register Addressing Mode? Operand can be a 16-bit register: Addressing Mode Description Example AX, BX, CX, DX, SI,

Instruction per cycle in RISC, Q. Instruction per cycle in RISC? One in...

Q. Instruction per cycle in RISC? One instruction per cycle: A machine cycle is total time taken to fetch two operands from registers perform ALU operation on them and store re

How to define a filename in dos, Q. How to define a Filename in DOS? Ea...

Q. How to define a Filename in DOS? Each file is given a name so that it can be referred to later. This name is termed as Filename. The filename in DOS can be up to eight alpha

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