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 a parsing, what is parsin? Source programmed statements are ob...

what is parsin? Source programmed statements are observed as tokens, recognizing, building block of language the task of scanning the source statement and classifying the diff

Why pointer variable to a function as an argument, Why pointer variable som...

Why pointer variable sometimes desirable to pass a pointer to a function as an argument? Frequently, a called function needs to make changes to objects declared in the calling

What is over-clocking, Overclocking is the process of making a computer or ...

Overclocking is the process of making a computer or component operate faster than the clock frequency particular by the manufacturer by modifying system parameters. One of the most

Example on multi-statement forall construct, Q. Example on Multi-statement ...

Q. Example on Multi-statement FORALL construct? The subsequent statements set every element of matrix X to sum of its indices.  FORALL (i=1:m, j=1:n)      X(i,j) = i+j an

What is the need of modem in data communication, What is the need of MODEM ...

What is the need of MODEM in data communication? Need of Modem: Modems are utilized to interface computer networks, computers and other terminal equipment for radio channels

Risk detection, what is meant by risk detection in software project managem...

what is meant by risk detection in software project management

Assembler directives, Assembler directives: An assembler directive is ...

Assembler directives: An assembler directive is a statement to give direction to the assembler to perform the task of assembly process. Assembler directives control organizati

State the tips of timescale directive, State the Tips of timescale directiv...

State the Tips of timescale directive Include a `timescale directive at the top of each module, even if there are no delays i n the module, since some simulators may require th

Explain about computer architecture, Explain about Computer architecture ...

Explain about Computer architecture Computer architecture is the conceptual design and fundamental operational structure of a computer system. It is a blueprint and functional

Selection - artificial intelligence, Selection - artificial intelligence: ...

Selection - artificial intelligence: However the first step is to choose the individuals that will have a shot at becoming the parents of the next generation. Hence this is kn

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