In this blog I am trying to elaborate the concept of what is
DLL stands for dynamic link library. A DLL is a library that
contains code and data which can be used by more than one program at the same
time, with the help of a DLL; program can be modularized into separate
components. For example, Microsoft Word is editing a document, the printer DLL
file does not need to be loaded into RAM. If the user decides to print the
document, then the Word application causes the printer DLL file to be loaded
and run. Additionally, updates are easier to apply to each module without
affecting other parts of the program. For example, you may have a payroll
program, and the tax rates change each year. When these changes are isolated to
a DLL, you can apply an update without needing to build or install the whole
The following list describes some of the files that are
implemented as DLLs in Windows operating systems
ActiveX Controls (.ocx) files
An example of an ActiveX control is a calendar
control that lets you select a date from a calendar.
Control Panel (.cpl) files
An example of a .cpl file is an item that is
located in Control Panel. Each item is a specialized DLL.
Device driver (.drv) files
An example of a device driver is a printer
driver that controls the printing to a printer.