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 are the types of operations required for instructions, What are the va...

What are the various types of operations required for instructions?  Data transfers among the main memory and the CPU registers Arithmetic and logic operation on data

Explain the term overlays, Explain the term Overlays. An overlay is an ...

Explain the term Overlays. An overlay is an element of program that has the same load origin as several other part of the program. These are used for reduce the main memory req

Explain how the different access methods work, Question: (a) Primary an...

Question: (a) Primary and secondary memory differs in their way they access data: (i) Mention the four generic access methods usually present in a computer system. (ii) E

What are the disadvantages of a vpn implementation, What are the Disadvanta...

What are the Disadvantages of a VPN implementation The greatest disadvantage of a VPN implementation is its non-flexibility to accept unknown locations. VPN works extremely wel

Define handshaking, Define Handshaking. Handshaking is a method commonl...

Define Handshaking. Handshaking is a method commonly used to accompany ever data item being transfer with the control signal that show the presence of data in the bus. The unit

Avoiding local minima of multi-layered networks, Avoiding Local Minima of m...

Avoiding Local Minima of multi-layered networks-Artificial intelligence : The error rate of multi-layered networks over a training set could be calculated as the number of mis

Recurrence relation, Take the following recurrence relation consider only f...

Take the following recurrence relation consider only for n = 2k for integers k ≥ 1: T(2) = 9, and for n ≥ 4, T(n) = n + T(n /2). Three students were working together in a stu

Various ways of floating point representation in memory, Describe the vario...

Describe the various ways of floating point representation in memory. What is the importance of normalizing the mantissa in this representation? Explain it by example(s)?

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