Dynamic Loading and Dynamic Linking in Memory Management

Dynamic loading is the process in which one can attach a shared library to the address space of the process during execution,Dynamic linking is similar to dynamic loading

Dynamic Loading

In our discussion so far, it has been necessary for the entire program and all data of a process to be in physical memory for the process to execute. The size of a process has thus been limited to the size of physical memory. To obtain better memory-space utilization, we can use dynamic With dynamic loading, a routine is not loaded until it is called. All routines are kept on disk in a relocatable 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 to see whether the other routine has been loaded. If it has not, the relocatable 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.

The advantage of dynamic loading is that an unused routine is never loaded. This method is particularly useful when large amounts of code are needed to handle infrequently occurring cases, such as error routines. In this case, although the total program size may be large, the portion that is used (and hence loaded) may be much smaller. Dynamic loading does not require special support from the operating system. It is the responsibility of the users to design their programs to take advantage of such a method. Operating systems may help the programmer, however, by providing library routines to implement dynamic loading.

 Dynamic Linking and Shared Libraries

Dynamic linking is similar to dynamic loading. Here, though, linking, rather than loading, is postponed until execution time.

This feature is usually used with system libraries, such as language subroutine libraries. Without this facility, each program on a system must include a copy of its language library (or at least the routines referenced by the program) 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. The 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 the stub is executed, it checks to see whether the needed routine is already in memory. If it is not, the program loads the routine into memory. Either way, the stub replaces itself with the address of the routine and executes the routine. Thus, the next time that particular code segment is reached, the library routine is executed directly, incurring no cost for dynamic linking.

Under this scheme, all processes that use a language library execute only one copy of the library code.

Keywords: dynamic loading, dynamic linking, shared libraries, memory management, definition of dynamic linking,



advance-java,2,advancejava,1,aktu entrance exam,1,aktu exam schedule,1,ASP,1,bare machine,1,base register and limit register,1,Basic Computer network questions,1,C Programming,15,C Plus Plus,1,C Programming,2,C Programming MCQ,2,C Programming Questions,2,C programming study material for gate exam,13,CBNST Program,1,Childcare,1,CJ,2,Cloud Computing,1,components of use case diagram,1,Computer architecture based questions for gate exam,11,Computer Network,3,Computer Network Study Material,4,Computer network study material for gate,2,Computer Networks,7,Computer Science Study Material for Gate,20,computer science study material for gate exam,37,content based image retrieval content based image retrieval system,1,contiguous memory allocation,2,Core Java,8,COre Java Interview Questions,1,core java interviews questions,1,cyber crime report,1,Cyber crime status,1,cybercrime and security,1,cybercrime examples,1,Data link Layer Questions,1,Data Mining,1,Data Structure Questions,1,Data Transmission Architecture,1,Data Transmission in wsn,1,DBMS,4,dbms question paper,1,DE,1,Different types of addressing modes,1,Digital Electronics,1,DS,1,dynamic linking,1,dynamic linking in memory management,1,Electroencephalogram,1,File Handling,1,file management in operating system notes,1,FOC,1,Fundamenatl of Computer,1,Gate 2017,5,Gate 2017 Admit card,1,Gate 2017 Exam Schedule,1,Gate 2017 Syllabus,1,gate 2018,1,gate cse study material,1,gate practice set,10,gate study material for computer science,19,Gate study material for computer science 2017,1,GatePreviousYear,1,General,3,HCL Aptitude Test,1,HR Interview Questions,1,HTML,1,Image Processing,1,Important Date of Gate 2017 Exam,1,Information Security Policy,1,internal and external fragmentation,1,JS,1,lagrange's interpolation formula,1,lagrange's interpolation formula examples,1,Looping in C,1,MComputing,1,memory fragmentation,1,memory management,1,Motivational,4,NCER,2,Numerical Techniques Lab,1,OOT,1,Operating System,10,Operating System Objective Questions,4,Operating System Questions Bank,1,Operating system questions for gate,1,Operating System Study material,2,operating system study material for gate exam,16,Operating system tutorial,2,ORACLE,1,page swapping,1,paged memory allocation,1,paged memory allocation in operating system,1,paging technique of memory management .paging technique,1,paging technique of memory management program in c,1,Pointer in C,5,Process based question for gate,1,Quiz on non conventional energy resources,1,Regression testing,1,relocation in memory management,1,relocation registe,1,relocation register,1,resident monitor,1,resident monitor in operating system,1,routing table,1,segmentation in memory management,1,segmentation in memory management in operating system,1,Servlet,1,session tracking,1,session tracking in java,1,session tracking in servlet,1,Software Engineering,8,Software Engineering baes study material for gate,1,software engineering interview questions,1,Software Quality Assurance,3,SPM,1,SQL,1,Structure in C,1,Study Material for gate Computer Science,11,swapping in memory management,1,swapping in operating system,1,TCS Code Vita,1,Technical Questions from DBMS,1,Thrashing in Operating System,1,Threads concept in operating system,1,Tips to Learn Coding,1,Top 30 Core Java Interview Questions with Answer,2,top down approach,1,top down approach in programming,1,Types of operating system,1,UML,1,use case diagram explanation,1,website uses cookies,1,what is cookies website,1,What is process control block ?,1,what is software testing?,1,Wireless Sensor Network,3,worst fit algorithm for memory allocation,1,XML,1,
Computer Science Junction: Dynamic Loading and Dynamic Linking in Memory Management
Dynamic Loading and Dynamic Linking in Memory Management
Dynamic loading is the process in which one can attach a shared library to the address space of the process during execution,Dynamic linking is similar to dynamic loading
Computer Science Junction
Loaded All Posts Not found any posts VIEW ALL Readmore Reply Cancel reply Delete By Home PAGES POSTS View All RECOMMENDED FOR YOU LABEL ARCHIVE SEARCH ALL POSTS Not found any post match with your request Back Home Sunday Monday Tuesday Wednesday Thursday Friday Saturday Sun Mon Tue Wed Thu Fri Sat January February March April May June July August September October November December Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec just now 1 minute ago $$1$$ minutes ago 1 hour ago $$1$$ hours ago Yesterday $$1$$ days ago $$1$$ weeks ago more than 5 weeks ago Followers Follow THIS PREMIUM CONTENT IS LOCKED STEP 1: Share. STEP 2: Click the link you shared to unlock Copy All Code Select All Code All codes were copied to your clipboard Can not copy the codes / texts, please press [CTRL]+[C] (or CMD+C with Mac) to copy