Permanently resident pages - main memory, Computer Engineering

Assignment Help:

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


Related Discussions:- Permanently resident pages - main memory

Explain what are the different hazards, There are situations, called hazard...

There are situations, called hazards that stop the next instruction in the instruction stream from implementing during its designated clock cycle. Hazards decrease the performance

Illustrate about packet switching, Q. Illustrate about Packet switching? ...

Q. Illustrate about Packet switching? Packet switching is used to avoid long delays in transmitting data over the network. Packet switching is a technique that limits the amoun

Computer systems architecture, Assume that you are working in a software co...

Assume that you are working in a software company as a programmer and a bank is your company's client. The Bank is a most popular and one of the leading banks in Malaysia. Your

What is configuration, What is configuration?  Turing  machine  compute...

What is configuration?  Turing  machine  computes,  changes  occur  in  the  current  state,  the  current  tap contents  and  the  current  head  location. A  setting  of  the

Computer graphics, what isAdvantages of scan line algorithm, Computer Graph...

what isAdvantages of scan line algorithm, Computer Graphics?

The information on the current screen, How do you find the information on t...

How do you find the information on the current screen? The information on the present screen can be found by SYSTEM ? STATUS command from any menu.

Main problems with evaluation functions, Main problems with evaluation func...

Main problems with evaluation functions: Superlatively, evaluation functions should be quick calculates. Wherever is chance they take a long time to estimate, so after then le

What are micrographics, What are micrographics? A micrographic is an im...

What are micrographics? A micrographic is an image or photographic reproduction of an object which is then changed to film. Micrographics are frequently used for permanent reco

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