The gold standard of operating systems...
-> Colin Percival is the developer of the Tarsnap online backup service and the portsnap tool for updating FreeBSD
Colin Percival is also the original developer of bsdiff, a binary patching utility. I seem to recall reading somewhere that bsdiff is used by Google for patching Android and Play Store apps. I could be wrong about that, but I do seem to recall it. It is the same bsdiff which is on android.googlesource.com.