[tejuis]

Data is information about things and code is information about how to transform data. Every program transforms input data to output data. Code is interpreted by the computer. Data and code are encoded to bits for the digital computer.

[galaxyLogic]

That sounds enlightening to me.

Code is interpreted by the computer, Data is interpreted by Code !!!

But when we say "code is interpreted by computer" we are really saying "Code is interpreted by Code" right? Meaning the interpreter or compiler.

So how come this snake doesn't eat its own tail?

The answer, the MAGIC of computers, is that at the lowest level somehow Hardware is able to interpret Code .

[tejuis]

My answer tried to be as generic as possible and leave out the "real world" and implementation details in general. There are fundamental limitations to what you can express in four sentences...

Compilation is "just" an intermediate step between code and using it in an interpreter. The interpreter can be pure hardware, mix of hardware and software, or you can do it on paper yourself (given time). These are implementation "details". Also, to me code is not a synomym with software, since I'm not referring to programmability, only to the transformation aspect. Programmability is an implementation detail. You may perform a transformation with hardware only, as mentioned above. The hardware itself could be described with code, e.g. in Verilog language. Manufacturing a silicon chip based on Verilog code is also an implementation detail.

In fact your CPU/PC is hardware and it is making transformation from input data to output data. In this case, besides the other input data, like keyboard input and files on disk, you may consider the binary code as part of the input data. This is where the confusion starts to happen. This is an implementation detail and should not be confused with the general notion of utility we want to have. Code is "only" the means to an end. We want to do stuff with the machine. We want to transform input data to output data, since that is essentially what we are after. For the goal of getting stuff done, data and code are separate things.

When saying "data is interpreted by code", it is partially correct. First of all data carries meaning, as in meaning for people (the data user). Data is encoded to some format (which is also data, but implementation data) and you could say that this encoding is "interpreted". However, the encoding is "just" an implementation detail which depends on the machine you are trying to use for the transformation. When the computer paints pixels on your monitor, it transfers data bits through display driver, through HDMI protocol (for example), to monitor itself. There are plenty of "interpreters" on that path. On the screen the pixels could represent the letter "A" and that could carry meaning for you (depending on the other stuff on the screen). This is why I stated that data is information about things. Encoded data is an implementation detail and varies between implementations, but the "true" data is essential and implementation independent. It carries meaning and utility value. Essential data is not interpreted by code. The user (a person) interpretes the essential data.

Code is data for the compiler. The compiler transforms source code (input data) to object code (output data). Code is data also for the interpreter. Algorithm contains all the essential information about the data transformations to be performed, and code in form of programming language text, is an implementation of that algorithm in the specific programming language. Algorithm is programming language independent. It's fair to say that by code I mean the algorithm. But also an algorithm must be presented in some form or another, so its code. :)