Comment by detaro

Most people who remember "defragging" have no clue what it actually does, and those that do have no problem understanding the issue of "heap fragmentation".

And if you think that developers below the age of 25 are the main reason your standard Office apps are slow, I wonder when you think that trend started and what the workforce building them looks like.

Same with everything else that's part of what's "understand how file systems work" means for users. It's an abstraction that tells you nothing about the underlying hardware - not to mention the underlying hardware having evolved quite a bit over the past few decades.