There are many detailed differences between different kinds of computer systems. But one of the important features of the Wolfram Language is that it allows you to work and create material without being concerned about such differences.

In order to fit in as well as possible with particular computer systems, the user interface for the Wolfram System on different systems is inevitably at least slightly different. But the crucial point is that beyond superficial differences, the Wolfram System is set up to work in exactly the same way on every kind of computer system.

The commands that you give to the Wolfram Language kernel, for example, are absolutely identical on every computer system. This means that when you write a program using these commands, you can immediately take the program and run it on any computer that supports the Wolfram System.

The structure of Wolfram System notebooks is also the same on all computer systems. And as a result, if you create a notebook on one computer system, you can immediately take it and use it on any other system.

Although the underlying structure of Wolfram System notebooks is always the same, there are often superficial differences in the way notebooks look on different computer systems, and in some of the mechanisms provided for interacting with them.

The goal in each case is to make notebooks work in a way that is as familiar as possible to people who are used to a particular type of computer system.

And in addition, by adapting the details of notebooks to each specific computer system, it becomes easier to exchange material between notebooks and other programs running on that computer system.

One consequence of the modular nature of the Wolfram System is that its parts can be run on different computers. Thus, for example, it is not uncommon to run the front end for the Wolfram System on one computer, while running the kernel on a separate computer.

Communications between the kernel and the front end are handled by WSTP.