This is what I want to know, because, it could be strange, but in my universty i studied the microprocessor, ram, hard disk, c++ , java, assembly language, mantissas... etc , but... I do not know the essence of computer work, know exactly what I'm quoting you.
Well, I want learn how the computer works and for understand all about computer I decided make one, I see this site: www.mycpu.eu and it's very complete but he isn't explains the electronic foundations and physicists of what he has done to construct his computer (he not explains how he has...
I think the better unix OS is debian, but it's something complicated for using because need knowledge of shell script , so I recommend you to use Ubuntu.
And the server... you can turn your computer in server, there is a lot of software to can do this.