Unfortunately, Raspberry Pi is far from the simplest possible computer. In fact, from my understanding, the boot process for RPis is rather complex, in part bec

Unfortunately, Raspberry Pi is far from the simplest possible computer. In fact, from my understanding, the boot process for RPis is rather complex, in part because it needs to be initiated by the GPU. Besides 80s computers which were truly simple, perhaps it would be interesting for you to first learn about microcontrollers. 8bit ones such as AVR or MSP430 would be simplest. They can still be purchased, and for relatively cheap, so you could run your own code and explore as you wish. https://embeddedartistry.com/blog/2019/04/08/a-general-overview-of-what-happens-before-main/ https://embeddedartistry.com/blog/2019/04/08/a-general-overv... Note on Arduino: they consist of two things, hardware and software. It's a fine way to purchase a working board with an AVR microcontroller. However the software part (Arduino IDE, Arduino "language", associated libraries) are all made to hide the complexity of the hardware and make it as easy as possible to run code. This is quite fine for many people, but maybe not you.