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 is turnaround time, What is turnaround time? Turnaround time is th...

What is turnaround time? Turnaround time is the interval from the time of submission to the time of completion of a process. It is the sum of the periods spent waiting to get i

What are handshaking signals, a. Explain the hardware mechanism for handlin...

a. Explain the hardware mechanism for handling multiple interrupt requests. b. What are handshaking signals? Describe the handshake control of data transfer during input and out

What are different queues used, 1.Local queue -is a actual queue 2.Clus...

1.Local queue -is a actual queue 2.Cluster queue -is a local queue that is called as throughout a cluster of queue managers 3. Remote queue -structure explaining a queue

Functioning of registers, Functioning of registers: at any instance of time...

Functioning of registers: at any instance of time global registers and only one window of registers is visible and is addressable as if it were only set of registers. So for progra

State in brief about third generation electronic computers, Third Generatio...

Third Generation (1963-1972) The third generation introduced huge gains in computational power. Innovations in this time include use of integrated circuits or ICs (semiconducto

Explain the working of a demultiplexer, Explain the working of a demultiple...

Explain the working of a demultiplexer with the help of an example. Ans: 1:4 Demultiplexer: Fig.(a) demonstrates the logic circuit of a 1:4 demultiplexer. This has two NOT

Compare the memory devices ram and rom, Compare the memory devices RAM and ...

Compare the memory devices RAM and ROM. Ans. Comparison of Semi-conductor Memories RAM ands ROM The advantages of ROM are: 1. This is cheaper than RAM. 2. This is non-volatil

Write a verilog code to swap contents of two registers, Write  a  verilog  ...

Write  a  verilog  code  to  swap  contents  of  two registers  with  and without  a  temporary register? With temp reg : always @ (posedge clock) begin temp=b; b

Task gantt, The Task Gantt shows the various tasks being performed i.e., so...

The Task Gantt shows the various tasks being performed i.e., some type of activities by the set of processors attached to the parallel computer as shown in Figure . Task Gantt

What are modes of operation of centralized spc, What are modes of operation...

What are modes of operation of centralized SPC? In about all the present day electronic switching systems utilizing centralized control, only a two-processor configuration is

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