There's the c1(physical computer), and then there's the c2(os runtime), and then there's the c3(silicon) and then there's the c4(turing machine):

The c1 is the thing that has the web browser running on it.

The c1 is the thing that has the code editor running on it.

The c1 is the thing that has the compiler running on it.

The c2 is the thing that provides a virtual hardware interface for running programs.

The c3 is the thing that the virtual hardware interface interacts with.

The c3 is the thing inside the hard drive/graphics card/other component that the c2 talks to.

The c4 is the thing inside the processor that pre-processes, jits, or otherwise transforms commands from the c2 for the c3 so the c1 ... ... ...

Is this correct?

Sure, but you can also run non-trivial code in the web browser.

I wasn't being super-precise with my comment, and my point is that there is no one thing that "is the computer". There are many computers in your computer, and many definitions of what a computer is.

I've never had to go below the HAL, or inside the JIT, but to some people that's where "the" computer really is. If that's where the computer really is, then I'm not a computer programmer (HINT: I'm not, but I do write code sometimes and get paid for it).

So if I write code, but it doesn't tell the computer what to do, what am I even doing?

Well, I write code that gets consumed by pre-processors and lexers and parsers and compilers and linkers and build agents and I don't know how the soup works, and you probably don't either, you may know more or less of the of the alpha-bits in the soup, but it's still soup. The soup is turned into jello and fed to a virtual machine, which is a fake computer, but it works well enough.

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If I were to be more precise, I would say that there's a von Neumann machine C0 that is represented by some hardware abstraction layer C1 by a operating system kernel. There may be a virtual machine C2 running in the C1 context.

But, inside that C0 von Neumann machine there are a bunch of microprocessors that may be called computers that may have Turing complete instruction sets.

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Or you could say, anything that can be Turing complete is a computer, in which case your web browser is a computer (among many others).

The trick is to expand the definition of "tell the computer what to do."

You can tell the computer what to do by writing a program that passes through six levels of abstraction before the fate of any electrons is affected by what you wrote.

You can also tell the computer what to do by pushing a lot of keys on a keyboard. We're lucky; our keyboards have like a hundred keys on them. Some of our predecessors had eight switches and a ninth key or switch to "ACCEPT" the current switch-bank state.

You can also tell the computer what to do by causing patterns to be stored on magnetic or optical media and read back later.

You can also tell the computer what to do by plugging a wire into the back of it and varying voltages on that wire using another machine a hundred miles away.

Part of the art of programming is knowing that there are no bright, solid lines between these ways to tell a computer what to do (but for a given task, some are clearly more applicable than others ;) ).