Interesting. I'd say that for systems, defense-in-depth usually relies on various forms of maintenance, and consistent effort to maintain functional parity in r

Interesting. I'd say that for systems, defense-in-depth usually relies on various forms of maintenance, and consistent effort to maintain functional parity in redundancies. In other words, just having a redundancy or secondary system is not enough. There's a lot of care and feeding when a secondary uses a different method of achieving the same ends as the primary. That requires effort -- which is all too often skipped or falls out of common knowledge.