What are the three buffering approaches used in computers?

Basically, each different buffering method is suited for different things. Some support First in First Out Method and others Last in First Out. Think of a YouTube video, you want to watch it frombeginningto end right? So what if your buffer was going in the wrong way? It would start loading the end of the video first. Thats a big problem. The same goes for other video players. In downloading games or other types of downloads, download order isn't vital as you can't play without all the files. So essentially its about load order