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
My digital instructor when I studied electronics stated that a processor is nothing more than a million morons working at the speed of light.
What that means is a processor, or computer chip that tells the computer what to do, and can’t do anything unless told to do something. A processor has logic gates hard coded into the chip, known as firmware. Programs that you load is called software because it can be modified, firmware can’t. Think of the processor as a giant water works station, and a series of 1’s and 0’s tell the station what ‘gates’ to open (logic gates in a computer). This directs the flow of water to physically do something, such as turn on a light, turn off a light, open some more gates, etc. The water station knows what gates to open as the 1 would represent water ‘pressure’, (or voltage in our computer chip) and 0 would represent no pressure. By opening the series of gates, the information encoded by the water, tells the station where to direct this flow, and by doing so, determines the outcome of this flow. Note that all peripherals such as printers, etc, all have their own internal waterworks as well, in which the computers water station, would use a series of ‘pipes’ or a ‘logic bus’ as called in a computer, to pass this information onto whatever station it needs to deal with. And this peripheral would also have its own ‘firmware’, to understand the logic being passed on.
I know this is rather simplistic but I hope it gives you some idea of how a computer processes information. Basically, you feed it a series of data, which the processor interprets, which then directs the outcome of this data to do something. Some of this you see directly, such as change an image on the screen, others, are invisible, such as handling timers, interrupts, memory management etc, but nothing can occur without the processor being told to do something. It is not automatic, (but can be if it is an embedded system, but that’s a different discussion). Your home computer cannot do anything without being told to, and that’s where the operating system comes in, (think water station), which handles the ‘flow’ of water, or data, internally. Think of the operating system as a giant reservoir, which the amount of water is fixed, (data) and all it does is circulate through the system operating various gates, causing ‘work’, such as updating your screen when typing, etc. The water station also handles external ‘flow’, (think of this as say, water flowing from an outside source, such as an external reservoirs) and also directs this data to use the same set of ‘gates’. Regardless of what the software does, it all has to use the same set of gates. Like a physical water station, (at least in our scenario), the processor can’t be modified and is forced to use it’s hard coded ‘infrastructure’, and can’t create new gates, but can only use the ones it has access too. (Some gates are protected, but we won’t get into that as I am trying to keep it simple lol).
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