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

Read after write and write after write - data hazards, RAW  and WAW - Data ...

RAW  and WAW - Data hazards: RAW (read after write) - j tries to read a source before i writes it, hence j wrongly gets the old value .This is the most usual type of

Which translator perform macro expansion, Which translator perform macro ex...

Which translator perform macro expansion, is called? Ans. Macro pre-processor perform macro expansion.

How to working in dreamweaver, Q. How to Working in Dreamweaver? Let's ...

Q. How to Working in Dreamweaver? Let's now start our journey into the realm of Dreamweaver. We begin with typing in a few test lines in Design view. See that how our work area

What are the uses of interactive reporting, What are the uses of interactiv...

What are the uses of interactive reporting? The user can actively control data retrieval and show during the session.  Instead of an extensive and detailed list, you make a ba

How are problems of clock skew minimized, How are problems of clock skew mi...

How are problems of clock skew minimized? Clock skew, when done right, can also benefit a circuit. This can be intentionally introduced to reduce the clock period, at that the

Fitness function - canonical genetic algorithm, Fitness function - canonica...

Fitness function - canonical genetic algorithm: Conversely the fitness function will use an evaluation function to calculate a value of worth for the individual accordingly th

What property of the architecture of 3g networks, Question: (a) Explain...

Question: (a) Explain how a Mobile Terminating call, from a PSTN phone, is processed in a GSM network. Illustrate your answer with a diagram. (b) Top-Net, a new telecommuni

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 write-back or copy-back protocol, What is write-back or copy-back p...

What is write-back or copy-back protocol? For a write operation using this protocol during write-hit: the method is to update only the cache and to mark it as updated with an a

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