Once it was all so simple...
- There weren't LPARs.
- Most installations had only 1 or at most 2 CECs.
- There wasn't such a thing as a Sysplex (let alone a Parallel one).
- There was only one processor type (pool).
- Things only changed rarely.
- Changes were manual.
Now things are so very different. Stick dirty great "not" signs in front of the previous list and you'll get a flavour of today's reality and that of the future.
Now most customers have to manually maintain a spreadsheet (or similar) recording the details of systems and LPARs - by hand.
Shouldn't systems be self-documenting? Particularly if they're going to be dynamic.