Search your Topic HERE....

January 30, 2014

Difference Between Dynamic Loading and Dynamic Linking

17 comments

sponsored links

Dynamic loading is used to obtain better memory-space utilization. With dynamic loading a routine is not loaded until it is called. All routines are kept on disk in a re-locatable load format. The main program is loaded into memory and is executed. When a routine needs to call another routine, the calling routine first checks whether the other routine has been loaded or not. The re-allocatable linking loader is called to load the desired routine into memory and to update the program's address tables to reflect this change. Then, control is passed to the newly loaded routine. Loading with bad time dynamic link libraries takes a little longer since, the loader has more work to do, but it saves a lot of disk space that would have been wasted with duplicate copies of every module.

The concept of dynamic linking is similar to that of dynamic loading. Rather than loading is being postponed until execution time, linking is postponed. This feature is usually used with system libraries, such as language subroutine libraries. Without this facility, all programs on a system need to have a copy of their language library (or at least the routines referenced by the program) included in the executable image. This requirement wastes both disk space and main memory. With dynamic linking, a stub is included in the image for each library-routine reference. This stub is a small piece of code that indicates how to locate the appropriate memory-resident library routine, or how to load the library if the routine is not already present.

When this stub is executed, it checks whether the needed routine is already in memory. If the routine is not in memory, the program loads it into memory. Either way, the stub replaces itself with the address of the routine, and executes the routine. Thus, the next time that code segment is reached, the library routine is executed directly, incurring on cost for dynamic linking. Under this scheme, all processes that use a language library execute only one copy of the library code. 

Sai Spandana. Kotturi
 sponsored links

17 comments:

  1. Thanks spandana. Please provide more. About DMA and all. Thank you.

    ReplyDelete
  2. Hi, any news for upcoming SBI clerk notification.......

    ReplyDelete
    Replies
    1. I am also waiting for this.pls anybody tell abt sbi notification

      Delete
  3. Assam Gramin Vikash Bank Notification is out.It is in employment news 1st feb 2014 edition and also will in official website by 1st feb 2014

    ReplyDelete
  4. aak paaka aa rha hai po3 result..pakki kabhar

    ReplyDelete
  5. 8 pm ..mere dost ke uncle ibps me hai wo bata rha tha...all the best

    ReplyDelete
    Replies
    1. chupkar bhosdi ke patak ke chodunga kukur sale itna hi ibps main link hai to maa chudane ke liye result ka intezar kar raha hai

      Delete
    2. chdu bakar ki aulaad jab aayega na to kud he dekh lene..mc bc

      Delete
  6. mam,quiz for IT officer plzzzzzz.............

    ReplyDelete
  7. hi mam,
    thanks for this..
    i request u to pllzz provide more info about databases and networks as it covers 50% of prof knwldg syllabus...
    and also needed it officer quizz thankuu...

    ReplyDelete
  8. may be po3 results will come by today evening,bcz po2 validity is finished by today.so hope for the best....

    ReplyDelete
  9. Ramandeep singh Urf MontyJanuary 31, 2014 at 4:57 PM

    hello can anybody tell me, whn po-3 result gonna declare.....?

    ReplyDelete
    Replies
    1. lo oopar ham kya kisi racipy ki baat kar rhe ha i

      Delete
    2. Phele Recipe ka spelling sik lay uskay baad kisi ka post ka comment dena.

      Delete
  10. Very useful.. Thank you..

    ReplyDelete

Related Posts Plugin for WordPress, Blogger...