@El_Duduarino
Just for kicks, you should look at the Linux 0.9 kernel source (the one that Linus did all by himself). It's pretty cool for a one-man effort, but it was pretty limited. If I remember correctly, it only supported 4MB of memory (because that's what Linus had, so he could not test larger configurations), only IDE disk drives (hosting only the Minix filesystem) and only VGA text mode; XFree86 only came a couple years later. SCSI, USB, "proper" filesystems, all those other things have been added by thousands of other people over the course of the last ten years (Linux first booted at roughly the same time that CBM went bust). Linus has been contributing code since the project become public, but his role has increasingly become one of architect and project manager.