Linus Thorvalds wrote git in around two weeks. The concepts behind are really simple (as is true for most source code versioning systems that use content addressing by cryptographic hashes). Huh, but it's now around 70k lines of code. Because I'm hacking on a similar version control system, I made some tests. I added the whole DragonFlyBSD source tree (/usr/src) into a git repository (git add . && git commit). Adding it took around 4.5 minutes and commiting it another 1.5 minutes, so in total it took 6 minutes. The git repository uses 154 MB. The same with my very early version control system takes around 5 minutes and consumes 139 MB. The original files consume 387 MB in total.

Did I mentioned that it's written in Ruby?