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

Explain about synchronous dram, Q. Explain about Synchronous DRAM? One ...

Q. Explain about Synchronous DRAM? One of the most broadly used forms of DRAM is synchronous DRAM (SDRAM). Unlike the conventional DRAM that is asynchronous SDRAM exchanges dat

Variable or compound expression - unification algorithm, Variable or compou...

Variable or compound expression - Unification algorithm: Here some things to note regarding this method are:  (i) There if really trying to match a constant to a different

The components of i-way infrastructure, What are the components of I-way In...

What are the components of I-way Infrastructure? There are three mechanism of the I-way infrastructure: Consumer access equipment Local on-Ramps Global informa

Two ways for restricting the value range for a domain, What are the two way...

What are the two ways for restricting the value range for a domain? By specifying fixed values. By stipulating a value table.

Explain direct memory access, Explain Direct Memory Access. A modest en...

Explain Direct Memory Access. A modest enhances in hardware enables an IO device to transfer a block of information to or from memory without CPU intervention. This task needs

Why we need to construct state transition diagram, Why we need to construct...

Why we need to construct state transition diagram Basically you need to construct a state transition diagram for each object with important behaviour. You need not construct on

Define superscalar processors, In scalar processors just one instruction is...

In scalar processors just one instruction is implemented per cycle which means just one instruction is issued for each cycle and only that one instruction is completed however the

Define password methods and biometric systems, Define the password methods ...

Define the password methods and Biometric systems for implementing client server network security. In cyberspace, buyers and sellers cannot notice each other. Also within video

Illustrate design of combinational circuits, The digital circuits that we u...

The digital circuits that we use now-a-days are constructed with NOR or NAND gates in place of AND-OR-NOT gates. NOR & NAND gates are known as Universal Gates as we can realize any

Convert the decimal number to excess-3 code, Convert the decimal number 430...

Convert the decimal number 430 to Excess-3 code ? Ans. Excess  3  is  a  digital  code  acquired  from  adding  3  to  every  decimal  digit  and  after that converting the res

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