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 basic function of keyboard, Q. Explain basic function of Keyboard? ...

Q. Explain basic function of Keyboard? Keyboard is the major input device for your computer. It is an accurate and fast device. The multiple character keys permit you to transm

What is the principle of locality, What is "the principle of locality"? ...

What is "the principle of locality"? It's the nature of the processes that they refer only to the small subset of the total data space of the process. I.e. the process frequ

Explain logical shift micro-operations, Q. Explain logical shift Micro-oper...

Q. Explain logical shift Micro-operations? In logical shift data entering by serial input to left most or right most flip-flop (which depends on right or left shift operations

What are the issues of software development, What are the issues of softwar...

What are the issues of software development One of main issues in software development today is quality. Software must be properly documented and implemented. The notion of sof

Find minimal expression for sop. draw gate network, Q Consider the followin...

Q Consider the following expression. Assume that complement inputs are available. F(A,B,C,D) = ∑m (1,2,6,9,10,14) + ∑d (4,7,8,11,12) a. Find minimal expression for SOP. Draw

Give regular expression for real number, Develop a regular expression for R...

Develop a regular expression for Real number and Real number with optional fraction (i) A regular expression for real number is [+ | -] (d)+. (d)+ (ii) A regular expression

Define hypertext verses hypermedia briefly, Define Hypertext verses Hyperme...

Define Hypertext verses Hypermedia briefly. Hypertext is fundamentally the same as regular text- this can be stored, read, searched or edited along with a significant exception

Explain how someone refine the ratio analysis, Refining the Ratio Analysis ...

Refining the Ratio Analysis Basically, refinement leads to purity. Thus to get a cleaner, more understandable and consistent design need to iterate analysis process.  R

Uml, what is uml ?

what is uml ?

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