There are a few ways to answer that question:
- Big box go bleep bloop
- The thing on my desk that runs Powerpoint
- A machine that manipulates data
- A Turing complete physical system
- Any pseudo-stochastic system that implements the 4th-order homologous group satisfying the Kauffmann criterion
These are all correct (except the last one, which I made up). So which one do we use?
What we really care about is actually building a computer. So let’s focus on a narrower question: what does a computer do?
example
When you want to watch a video on your phone, something like this happens:
- You search for the video by name. Your phone reads what you typed.
- Your phone transforms that data into a piece of data representing the video.
- Your phone outputs the data as a video.
This read-transform-output process is one way of thinking about computers. A computer is an object that:
- reads input from the user
- transforms that input into some kind of answer
- outputs the answer in a way the user can understand
This isn’t a rigorous or complete definition of a computer, but it’s a good start.
programs
Wait a second. Under our definition, isn’t a cooking pot a computer?
- It reads in a bunch of ingredients
- It transforms the ingredients
- It outputs delicious soup
The missing component is programmability — the ability to change behaviour based on a program, which is a list of instructions. A cooking pot will always behave the same way; you can’t turn it into a toaster by writing “toaster” on the side.
flexibility
What about an oven with multiple settings, like “fan”, “rice cooker”, “defrost” etc? That sounds like changing behaviour. Does that count as a program, and does that make an oven a computer?
When we talk about programmability, we need a certain level of power or flexibility. It’s not enough to just choose between different settings, or adjust the duration of cooking. A computer needs to be able to do things like “check whether this condition is true”, or “remember this value, and check it later”.
goal
So to build a computer out of roons, we’ll need to build a pattern that can:
- read our inputs
- transform that information into some kind of result, in accordance with a program we can change in flexible ways
- output the result in a way we can read
In the next tutorial, we’ll start tackling these tasks.
continue
