Slightly OT, but I've only ever used Git for version control. At the end of the article, the author mentions that Facebook uses (a custom version of) Mercurial instead of Git.
What are the benefits to using Mercurial over Git?
If I remember correctly, the reason Facebook switched to Mercurial from Git was because they needed to make some changes or add additional functionality and Mercurial is an easier system to do that with, apparently.
> For example, the Windows codebase has over 3.5 million files and is over 270 GB in size.
What takes up most of the space in the repo, is it just from code or are a lot of binaries in there? No doubt the windows code base is particularly large, but I would have though most of it would be slow moving.
This is speculation, but if they have design assets, sounds, videos, localizations, and other things that aren't technically code but are totally part of Windows, then I can definitely see why it'd balloon to that order of magnitude.
Same version control as Linux!
For Linux they don't use virtualized file systems.