Chapter Is Not Very Clear

What are Data Part1, Data Part2 … 3?
Is it some arbitrary way of dividing all data on a machine into smaller chunks and then create hash of that? Or is it each individual record?

Overall there are several questions and this chapter doesn’t provide the clear picture.


Came here to say exactly this. The author would do well to get some help from experts because the level of depth here makes me doubt they themselves understand this.