Computers are - ignoring emulation and things like that - physical machines that interact with the environment by reading inputs and writing outputs - reading w

Computers are - ignoring emulation and things like that - physical machines that interact with the environment by reading inputs and writing outputs - reading whether the space bar is pressed and making a pixel on the screen light up red. While their function is fixed at the lowest level - how they process individual instructions due to their physical circuits - they are highly configurable machines, they have billions of capacitors or magnetic domains that you can charge and discharge or align one way or another in order to control what exactly the machine does, how it translates inputs to outputs. Software - in the broadest sense - then is a description of how to configure a computer to achieve a certain input output behavior. It exists as a continuum of abstractness, from the idea in ones head, over the specification in a Word document, to the source code on GitHub, and the compilation result for a specific architecture on a flash drive. It is substrate independent, you can have the source code in your mind, store it on disk, or you can print it out. It is quite malleable, you can change it quite a bit without substantially altering it, at least at the more abstract end of the spectrum. Where you draw the boundary between Windows 7 and not Windows 7 seems pretty arbitrary, that is just a label. Is the concept in your head already Windows 7? Maybe. How many changes are you willing to do before you decide to call it Windows 8? Arbitrary decision. Does an added comment in the source make a new revision? If you want to. There will always be some tension between the abstract description of what Windows 7 is supposed to do and the concrete implementation of that ideas - including details like the formatting of the source code - and I do not see that we have to gain much be trying to precisely define where the borders are. That seems like trying to nail down where blue turns into green.