I searched all over the net about separation compilation but I'm really unsure of the resources I've read because they talk about the separate processes in compiling a program such as syntax checking, code optimization and converting to machine code....

Something tells me that this is not separation compilation.

I'd really appreciate it if someone can confirm what really is separation compilation..:)

There is no such thing as separation compilation. Maybe you mean separate compilation. It's where you compile things separately and then link object files together.