A little Slicing & Dicing of VM/370's inner workings

Let's take the USER DIRECT & USER DISKMAP files, slice them into columns with Notepad++, drop them into a Google Sheets spreadsheet and reconcile everything with their Hercules disk files. Sounds like a lot of work, and why the heck would you do all that? For Science! Well, maybe to get a better understanding of how this all works together to make VM/370 do it's magic.