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 instruction register and flags, Q. Explain about Instruction ...

Q. Explain about Instruction Register and Flags? The Instruction Register: It comprises the operation code (opcode) and addressing mode bits of the instruction. It assists in

What is a sparse matrix, What is a sparse matrix? Sparse Matrix A m...

What is a sparse matrix? Sparse Matrix A matrix in which number of zero entries is much higher than the number of non-zero entries is known as sparse matrix. The natural me

What is verilog, What is Verilog Verilog  language  is  still  rooted  ...

What is Verilog Verilog  language  is  still  rooted  in  it's  native  interpretative  mode.  Compilation  is  a means of speeding up simulation however has not changed the or

Temporary location, Compare zero-, one, two-, and three- address machines b...

Compare zero-, one, two-, and three- address machines by writing programs to compute                         X = (A + B x C)/(D - E x F) for every of the four machines.  Do n

Distributivity of connectives, Distributivity of Connectives : In our ...

Distributivity of Connectives : In our last analogy with arithmetic will involve a very well-technique need for playing around with algebraic properties. But assume there if w

What is a semaphore, What is a semaphore? Semaphore: It is a protecte...

What is a semaphore? Semaphore: It is a protected variable or abstract data type that constitutes the typical method for restricting access to shared resources as shared memo

Performance of pipelines with stalls, Performance of Pipelines with Stalls:...

Performance of Pipelines with Stalls: A stall is reason of the pipeline performance to degrade the ideal performance.                                             Average in

Smart card & e-cash, Smart Card & E-Cash E-cash storable smart cards ca...

Smart Card & E-Cash E-cash storable smart cards can kept and dispense cash electronically, making bills and coins lesser essential. It transfers funds over phone lines, making

What is the meaning of proper programming, What is the meaning of Proper pr...

What is the meaning of Proper programming Proper programming of the ports of the company's Web server through detection of IP addresses could be an excellent strategy or solut

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