choose Open Source OS for embedded application
 

hello, everyone.
I am newcommer with embedded applications using open source Operating System.
Now I still don't know which OS should I chose.
pls recommend me OS with the following criteria:
- open source and documented very good
- support many architectures such as ARM, PowerPC, MIPS,...
- easy to custom
- toolchain is avaiable
- many used people
- ...
thank you very much

I recommend Linux.