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 pages, What are pages? All programs and date are composed of f...

What are pages? All programs and date are composed of fixed length units known as pages. Each page consists of blocks of words that occupy contiguous locations in main memory

Dataflow computing, Dataflow Computing A different to the von Neumann m...

Dataflow Computing A different to the von Neumann model of computation is the dataflow computation model. In a dataflow model, control is fixed to the flow of data. The order o

Propositional truth tables, Propositional truth tables: There {X\t} is...

Propositional truth tables: There {X\t} is a substitution that replaces all occurances of variable X with a term representing an object t as:  ∀X. A is true if and only

Determine signed binary number, -8 is equal to which signed binary number ?...

-8 is equal to which signed binary number ? Ans. 10001000 is the signed binary number that equal to - 8.   To show negative numbers in the binary system, Digit 1 is utilized fo

Explain the various interface circuits, Explain the various interface circu...

Explain the various interface circuits.  An I/O interface having of circuitry required to connect an I/O device to computer bus. One side having of a data path with its associa

Does c have circular shift operators, No C don't have circular shift operat...

No C don't have circular shift operator. (Part of the reason why that is the sizes of C's types aren't precisely described----but a circular shift makes most sense when applied to

What is graceful degradation, What is graceful degradation? In multipro...

What is graceful degradation? In multiprocessor systems, failure of one processor will not halt the system, but only slow it down by sharing the work of failure system by other

Explain topology method used in lan technology in detail, Explain topology ...

Explain topology method used in LAN technology in detail. LAN Topologies: Network topology is a physical schematic that shows interconnection of the various users. There are

What are different edi components and edi services, What are different EDI ...

What are different EDI components and EDI services? Different EDI components and EDI services are illustrated as: Three main components including services in EDI System are

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