Ok, so I know that the alphabet of computers consists of only two symbols, or states: zero and one.
I also seem to understand how computers count beyond one even though they don’t have symbols for anything above one.
What I do NOT understand is how a computer knows* that a particular string of ones and zeros refers to a number, or a letter, or a pixel, or an RGB color, and all the other types of data that computers are able to render.
*EDIT: A lot of you guys hang up on the word “know”, emphasing that a computer does not know anything. Of course, I do not attribute any real awareness or understanding to a computer. I’m using the verb “know” only figuratively, folks ;).
I think that somewhere under the hood there must be a physical element–like a table, a maze, a system of levers, a punchcard, etc.–that breaks up the single, continuous stream of ones and zeros into rivulets and routes them into–for lack of a better word–different tunnels? One for letters, another for numbers, yet another for pixels, and so on?
I can’t make do with just the information that computers speak in ones and zeros because it’s like dumbing down the process human communication to the mere fact of relying on an alphabet.
In: 264
Well, the answer is that it “knows” because we tell it what to expect. Think of memory as a long long sequence of ones and zeros, and we break it into groups (bytes) with addresses that start at 0. When the computer starts, it knows what address to look at first, and what to expect there (code to start running to boot up). When running any program, we give it the starting address for that code, and when the code needs to look at data, the code supplies the data address and a description of the data that the programmer decided (look here, you’ll find an integer).
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