* Hardware Needs an Interface: Hardware components like your CPU, memory, and storage devices don't understand human-readable instructions like "print 'Hello, world!'". They only understand low-level machine code (binary instructions).
* The Operating System is the Translator: The operating system acts as a bridge between your software (like a program that prints "Hello, world!") and the hardware. It translates high-level instructions into the low-level language the hardware understands.
* Bootstrapping: Even to load the operating system itself, you need a very basic program called a "bootloader" that runs directly on the hardware. This bootloader is essentially a minimal operating system designed to get the real OS loaded.
What You Can Do Instead:
1. Bare-Metal Programming: You can write programs directly for specific hardware architectures. This involves learning assembly language and working at a very low level. It's incredibly complex, but it gives you a deeper understanding of how software interacts with hardware.
2. Embedded Systems: Embedded systems are often designed to run without a full-blown operating system. These systems might have their own custom firmware that allows you to display text on a screen.
In essence, "Hello, world!" requires a software layer (like an operating system) to interact with the hardware and display the text. It's impossible to do it directly without that software layer.