A dynamic link library
(DLL) is a dynamic reference archive with program codes whose functions are only loaded dynamically when a program is called. The components of the link archive are only loaded when the program
requires them. DLL modules provide basic functions such asdevice drivers, routines for memory, file and directory services
.dll, which enables access to an ISDN card.DLLs are used
in the Windows and OS/2
operating systems and can be used simultaneously by several applications. In addition, DLLs also enable programming language programming. DLLs contain important functions that control the internal software and hardware interfaces in certain operating systems. The file extension for DLL files is *.dll.