What is White Box and Black Box?

In SysML (Systems Modeling Language), a system model can be viewed from either a whitebox perspective or a blackbox perspective.

A whitebox view of a system model is an internal view that shows the system's components, their relationships, and how they work together to achieve the system's functionality. In other words, it provides a detailed, low-level view of the system's structure and behavior, showing the internal workings of the system. This type of view is useful for understanding the system's design and for making changes to the system's components.

On the other hand, a blackbox view of a system model is an external view that shows the system's inputs, outputs, and the system's behavior as a whole without going into the details of how it works internally. In other words, it provides a high-level, abstract view of the system's functionality, without showing how the system is implemented. This type of view is useful for understanding the system's overall behavior and for communicating the system's functionality to stakeholders who do not need to know the details of how the system works.

To summarize, a whitebox view of a system model shows the internal workings of the system, while a blackbox view shows the system's external behavior without revealing the details of its internal workings. Both views are useful for different purposes and are necessary for understanding and communicating the design and functionality of a system.

Another way to think of it, white box is similar to a transparent view while backbox is an opaque view.  A system modeler can see into the transparent box to see the inter workings but the modeler cannot see into an opaque box.