WHAT ARE DLLs AND ERRORS

Anyone who has used windows must be aware of the infamous '.dll' error whenever trying to do something.

 Although DLL files seem pretty important it's not very clear what they actually are.

DLL stands for Dynamic Link Library, the reason they are called "Library" is DLLs contain code that multiple programs can use at the same time.

Once the DLL file is loaded in a space in the memory any program that needs the code inside that DLL can access that space without the DLL having to be loaded again and again.

A simple example of this is the Device Driver, which contains the code which allows the windows and other softwares to communicate with the hardware. They allow multiple applications to access your GPU, keyboard or mouse at a time.

Since DLLs are only loaded when a programs specifically asks for them, they don't take a lot of space.

This modularity is useful for adding new functionality like game updates just by creating new DLLs instead of modifying the whole code.

So, if DLLs are so useful then why do they cause so many errors? 

When an application depends on lots of DLLs it runs into the risk of crashing when the DLL file is changed or updated.

The best example for this is the DirectX program that contains DLLs mostly used by games.

If you run a modern game in older DirectX versions it will produce a ".dll is missing" error because they don't have the modern updated DLLs required by that game. Newer DirectX versions have updated DLLs that can be used by both old and modern games but not Vice- a- Versa.