Cache coherency

Imagine you have lots of toys and you want to share them with your friends. Sometimes, two of your friends want to play with the same toy at the same time. This means they will argue and neither of them will be happy.

Computers have the same problem when they want to share information between different parts of the computer. If two parts of the computer want to use the same information, they can end up arguing over who gets to use it. This can cause the computer to slow down or even stop working.

Cache coherency is a way to make sure that all parts of the computer have the same information at the same time, and that they are not arguing over who gets to use it. Just like you can tell your friends to take turns with a toy, computers use cache coherency to make sure that different parts of the computer take turns using the same information.

Cache coherency works by keeping a copy of the information called a cache in different parts of the computer. If one part of the computer changes the information in its cache, it tells all the other parts of the computer about the change so they all have the same updated information. This way, when different parts of the computer want to use the same information, they all have the same version of it and don't argue over who gets to use it.

So, cache coherency is like making sure all your friends have the same information about a toy before they play with it, so they don't argue over who gets to use it. And just like how you can't play with a toy if your friend is already playing with it, cache coherency makes sure different parts of the computer take turns with the same information.