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

Two ways of producing a list within a transaction, What are the two ways of...

What are the two ways of producing a list within a transaction? By submitting a separate report. By using leave to list-processing.

Define edge triggered d flip flop, Define Edge Triggered D flip-flop? D...

Define Edge Triggered D flip-flop? D latch has only two inputs C(control) and D(data). The operation of a D flip-flop is a lot simpler and it has only one input addition to the

What is the size of the variant data type, The Variant data type has a nume...

The Variant data type has a numeric storage size of 16 bytes and can have data up to the range of a Decimal, or a character storage size of 22 bytes (plus string length),and can ke

Show the main drawback of cav disk, Q. Show the main drawback of CAV disk? ...

Q. Show the main drawback of CAV disk? The main drawback of CAV disk is that a lot of storage space is wasted because longer outer tracks are storing data only equal to the sho

What is overflow and underflow case in single precision, What is overflow, ...

What is overflow, underflow case in single precision(sp)? Underflow-In SP it means that the normalized representation needs an exponent less than -126. Overflow-In SP it mea

Explain about fundamental nature of a computer, Q. Explain about fundamenta...

Q. Explain about fundamental nature of a Computer? The fundamental nature of a Computer is as an information transformer. So a computer should be able to take input and process

Java, what is java?

what is java?

How is recursion handled internally, How is recursion handled internally? ...

How is recursion handled internally? Internally, every recursive call to a function requires storing the intermediate values of the parameters and local variables in a run time

Some of the advantages of b2b, Some of the advantages of B2B are: i) En...

Some of the advantages of B2B are: i) Enhanced customer satisfaction Code ii) Enhanced inventory system iii) Simple and cost effective marketing iv) Coordination among

Induction that your closed formula , Show by induction that your closed for...

Show by induction that your closed formula from (c) is the number of times that the given statement is implemented for a problem of size n.Note: if your proof is easily  a proof th

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