Permanently resident pages - main memory, Computer Engineering

Permanently resident pages:

Every virtual memory systems have memory areas that are "pinned down", for example cannot be swapped out to secondary storage, for instance:

  • Interrupt mechanisms usually rely on an array of pointers to the handlers for different types of interrupt (I/O completion, program error, timer event, page fault, etc.). If the pages containing these pointers or the code that they invoke were page able, interrupt-handling would become even more complicated and time-consuming; and it would be especially hard in the case of page fault interrupts.
  • The page tables are typically not page able.
  • Data buffers that are accessed outside of the CPU, for instance by peripheral devices that use direct memory access (DMA) or by I/O channels. Typically such devices and the buses (connection paths) to which they are connected use physical memory addresses rather than virtual memory addresses. Even on buses  with  an  IOMMU,  that  is  a  special  memory  management  unit  that  may  translate  virtual addresses used on an I/O bus to physical addresses that transfer can't be stopped if a page fault take place and then restarted when the page fault has been processed. So pages that contain locations to which or from which a peripheral device is transferring data are either enduringly pinned down or pinned down whilst the transfer is in progress.
  • Timing-dependent kernel/application cannot stand the varying response time caused by paging.

1356_Permanently resident pages.png

Posted Date: 10/13/2012 5:38:23 AM | Location : United States







Related Discussions:- Permanently resident pages - main memory, Assignment Help, Ask Question on Permanently resident pages - main memory, Get Answer, Expert's Help, Permanently resident pages - main memory Discussions

Write discussion on Permanently resident pages - main memory
Your posts are moderated
Related Questions
How and when race conditions happen in process control? How can it be avoided? b. Differentiate among following functions giving related syntax: (i) fork and vfork (ii) w

Explain the Storage Class Static The Storage Class Static : Static declarations have two important and distinct uses. The more elementary use is to allow a local variable to

Q. Find 9's complement for decimal number? The 9's complement is achieved by subtracting every digit of number from 9 (the highest digit value). Let's assume that we want to si

Object Repository means not a set of objects. It's a common repository for all the people (Testing, Developers) for seeing all the data in one Login. For example QA needs

Write a program that input (from the user) the number of hours worked and hours pay rate for employees and output their total pay. The program should process an arbitrary number of

What are the features of ABAP/4 Dictionary? The most significant features are: Integrated to aABAP/4 Development Workbench. Active in the runtime environment.

World Wide Web (WWW) began as a text-only medium. First version doesn't even have the capability to include graphics on a page. Today's Web sites include sound animation, graphics,

What  are  universal  gates.  Construct  a  logic  circuit  using  NAND  gates  only  for  the expression x = A . (B + C). Ans. Universal Gates: NAND and NOR Gates both are t

Q) a.Define the programming-language features that are required to properly  support concurrent programming? b. What support do these features need from the operating system?

how can get payment