A dynamic-link library (DLL) file is an executable file containing a collection of small modules, which allows the programs to share code and other resources necessary to perform particular tasks. The DLL file lets the executable file (.exe) to communicate with a specific device such as a printer or may contain source code to execute the particular functions.
A DLL can be used by several applications at the same time. Some of these are provided with the Windows operating system and available for any Windows application. Other DLLs are written for a particular application and are loaded with the application.
These files are created to make sure that multiple applications could access the common resources and information at the same time, in order to conserve memory. It also allows the user to edit the coding of multiple applications at once, without changing the applications themselves.
File extension: .dll
Mime type: application/x-msdownload, application/octet-stream, application/x-msdos-program
When a program is launched, links to the required .dll files will be created. This link can be either static link or a dynamic link. A static link will be in use as long as the program is active and remains constant throughout the execution process. A dynamic link is created by the program only when it is needed. Dynamic links help programs use resources, such as memory and hard drive space more efficiently.
Advantages of DLL file
These DLL files are not loaded into random access memory (RAM) along with the main program; but will be called only when needed. Hence space will be saved in RAM. For example, when editing a Microsoft Word document, the printer DLL file will not get loaded into RAM when the word is loaded. Instead when the user decides to print the document, only then the printer DLL file gets loaded and a call is made to print.
These DLL files can be used by more than one program at the same time. This reduces the space and hard drive memory. For example, if several programs need to perform the same action then that action can be placed into a .dll file or library. Now, all these program modules can use this single .dll file and access the information needed to perform their task. This saves space and makes it easier when that particular routine needs to be updated.