What exactly do people mean when they say the NES was an 8 bit console? I know that a bit in computer terms is a single piece of data that can be 1 or 0, but 8 of these doesn’t sound like enough to do all of the things you’d need to play a game like Mario. So what element of the console was 8 bits?
In: Technology
The “8-bit” refers to the word size, that is how big a piece of data the CPU can work on at once. Now, if you look at 8 bits, that gives you 256 (2^8) possible values… but that can’t be right surely? You always see numbers bigger than that, your XP or money in an RPG. Well you can work on larger values, but it tends to be quite slow, like splitting it into a high number and low number and working on them carefully “Okay, the player has earned 50 Gil… which we add to the 250 in their bag… and that rolled over, so lets add a 1 to the next part of their cash value. Okay they bought something for 2,000 gil, how do I change each part so this works out…” and this takes a lot more instructions and thus more time.
So things generally try to stick to 255 or less, like number of potions you can carry, maximum level, but really it’s about the amount of colours and sprites the system can handle, because putting things on the screen is the hardest job in a console. So for the NES you have 255 ’tiles’ each 8×8 in size, a ? block in Super Mario is 16×16, so there’s 4 tiles used already. You can get more out of tiles by changing the colours, like how the clouds and bushes in Super Mario are the same *tile*, just one is white and one is green.
So the most ELI5 answer is “it can do maths really quickly only if the numbers are 0-255, so keep all the code talking about graphics or things you do all the time below that number”.
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