If your goal is to produce Linux, you've picked the wrong goal; just use Linux! But back when computers were simpler, in the months April – August 1991, one absolutely could make an OS kernel where things “seem to work” in four months.
Ok, you're very clever. Replace "building an OS" with "proving the Goldbach hypothesis" or something. I was just giving an example of what I thought was a challenging project. Clearly for you it wouldn't be challenging.
