RP 1215 - Software Compatibility Guidelines: Components: Notes

Components (DLL's and OCX's) allow applications to share functions and procedures rather than loading a copy of the same file repeatedly. The disadvantage of components is that they are operating system specific; for example, a 16-bit DLL is not compatible with a 32-bit DLL of the same name. Another is that components may be different based upon the software compiler version. Finally, if an application's install program does not check the disk contents for a like-named component before writing the new component, a component versioning problem may occur that will make a previously loaded application behave improperly, or not at all.