I would not count something as "not written by Apple" just because it is compiled with gcc. I did neglect Apache, python, and such. I was just thinking of the

I would not count something as "not written by Apple" just because it is compiled with gcc. I did neglect Apache, python, and such. I was just thinking of the BSD type utilities. As far as OS licenses, there are cheaper ways to get a base OS than Windows or Solaris. I don't remember what I used to pay for QNX licenses back in the '90s for devices we used to build, but they were cheap enough that it didn't matter. What google does in their large farms just needs the bare core of an OS, I'm sure they could write their own for under $100M. I'm just reinstalling a Tiger machine. I'll list off all the executable files and see if I can find a sane way of estimating author. It should make an interesting pie chart.