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 real time clock, Real time clock A real-time clock keeps the t...

Real time clock A real-time clock keeps the time in real time - i.e. in hours and minutes. Software for the real-time clock comprises an interrupt service procedure which is c

Flynns categorization, Flynn's Categorization Flynn's Categorization is...

Flynn's Categorization Flynn's Categorization is based on multiplicity of data streams and instruction streams observed by CPU at the time of program execution. Let I s and D

What is problem statement, What is problem statement The problem state...

What is problem statement The problem statement is crucial for any analysis. Problem statement is general description of the user's desires, and difficulties. The motive of pr

What is the function of the correction system, What is the function of the ...

What is the function of the correction system? The correction system handles changes to internal system components. Like as objects of the ABAP/4 Dictionary.

Execution-modes of a multiprocessor, Q. Explain Execution-modes of a multip...

Q. Explain Execution-modes of a multiprocessor? Execution-modes of a multiprocessor: Several modes of multiprocessing comprise parallel execution of programs at (i) Fine Grain

Determine about the logical shift, Logical shift A logical shift operat...

Logical shift A logical shift operation transfers 0 through serial input. We apply symbols shl and shr for logical shift left and shift right microoperations, examples:. R1

Differentiate aggregation and containment, Aggregation is the relationship ...

Aggregation is the relationship among the whole and a part. We can add/subtract some properties in the part (slave) side. It won't affect the entire part. Best example is Car,

What is locality of reference, What is locality of reference? Analysis ...

What is locality of reference? Analysis of program represents that many instructions ion localized areas of the program are implemented repeatedly during some time period, and

What are the advantages of public key cryptography, What are the advantages...

What are the advantages of Public Key Cryptography? Advantages of Public Key Cryptography are illustrated in below: a) Increased convenience and security and b) Electro

What is simd, What is SIMD? Single Instruction stream, Multiple Data st...

What is SIMD? Single Instruction stream, Multiple Data stream (SIMD) shows an organization that contains many processing units under the supervision of a common control unit. 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