Hello;
I have questions confuse me very much, when we install linux on empty hard disk ,how the linux compile ?
and if there is compiler ,how can it install?
shortly, what the first program run when we install linux?

With my respect.

Most Linux distributions are distributed in binary from (already compiled). The distribution will include a compiler so that you may RE-compile any program you wish including the kernel.

When "Linux" is installed on a clean hard disk it is just copied from the CD to the hard disk .
As for your question about the 1st program run.... well it depends on where you want to start, quite a few programs run as the system starts 1st the there is a POST (Power On Self Test) this is a program which is included with your hardware

I guess the 1st user land program started by the kernel is init. This program gets the ball rolling for everything else.

I am not sure if this answers your question? But I think its a start.

Thank you mhiggins very much.