You might want to learn how a computer boots up from the get go. In a nutshell, BIOS/UEFI (it's firmware code in a CMOS chip) fires off the sequence of events that start up the hard drive. Once the hard drive is fired up then the operating system takes over and thus its installed drivers.
I bet there's a "Dummy'"s book on this or some other publisher. I remember reading a book like this waaay back in the day while in the fourth grade doing a research report on the advent of the PC. It was one of my favorite research reports. God, I wish I still had it. My mom just might, but who knows where that's at.
- - - Updated - - -
Off topic and a little more complicated, this is analogous to the process of how a commercial jet is started. What happens is that the pilot starts something called the auxiliary power unit (APU). This is a very small jet engine in the rear end of the aircraft. Sometimes if you're sitting in the back of the aircraft you can smell a thick aviation fuel smell back there because of the firing off the APU. Once this small jet engine is fired up its bleed air (highly compressed hot gas) and electric power generation are used to fire up each main engine one at a time. You typically fire up the engine on the right first then the left. On the overhead you have an ignition switch LEFT and RIGHT. This is NOT for left and right engine selection but for the choice of LEFT or RIGHT igniters in the engine its self. You typically chose ignitor LEFT at the start of the day and the RIGHT igniter then the LEFT, onward over the course of the day to reduce wear and tear. You use BOTH igniters at the same time in an emergency situation to desperately try to restart the engine. You also keep the switch at the both position while climbing out. Again, in case of an emergency. The igniters are like what you might see in a furnace, but way more advanced.
Anyway, just an interesting parallel in how a BIOS/UEFI passes on commands to fire up a hard drive to get the OS running and how a plane uses a small engine (the APU) to start its larger engines.
BTW, jets without an APU use a portable engine start cart you might see on the tarmac at the airport. There's a name for these that escapes me at the moment.
Anyway... LOL!
