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

State the datatypes of verilog, State the datatypes of Verilog Verilog....

State the datatypes of Verilog Verilog. Compared to VHDL, Verilog data types are very simple, easy to use and very much geared towards modeling hardware structure as opposed to

Explain biometric systems, Explain Biometric Systems Biometrics is the ...

Explain Biometric Systems Biometrics is the science of measuring physical properties of living beings. Biometric Authentication (1) Biometric authentication is the aut

Computer graphics, what is boundary filling explain with example

what is boundary filling explain with example

Select-options and parameters statement, The fields specified by select-opt...

The fields specified by select-options and parameters statement cannot be grouped together in the selection screen.  No, It can be grouped together in the selection screen

Define the firewall design policy, Define the Firewall Design Policy ...

Define the Firewall Design Policy A lower-level policy that describes how the firewall will handle prevention of access and filtering of services as defined in the above net

Describe independent loops in fortran, Q. Describe Independent Loops in for...

Q. Describe Independent Loops in fortran? HPF offers extra opportunities for parallel execution by employing the INDEPENDENT directive to declare the iterations of a do-loop is

What is mini frame size where propagation speed is 200 m µs, A CSMA/CD bus ...

A CSMA/CD bus spans a distance of 1.5 Km. If data is 5 Mbps, What is minimum frame size where propagation speed in LAN cable is 200 m µs. Usual propagation speed in LAN cables

Describe about immediate addressing mode, Q. Describe about Immediate Addre...

Q. Describe about Immediate Addressing mode? When an operand is interpreted as an immediate value for example LOAD IMMEDIATE 7 it is actual value 7 which is put in CPU register

Why disable statements are not allowed in functions, Why disable statements...

Why disable statements are not allowed in functions? If  disble  statement  is used  in function,it  invalids  function  and  its  return  value.  So  disable statements aren't

What is scan, What is "Scan"? Scan Insertion and ATPG helps test ASICs ...

What is "Scan"? Scan Insertion and ATPG helps test ASICs (e.g. chips) during manufacture. If you know what JTAG boundary scan is, then Scan is the similar idea except that it i

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