Verify vs Hardware Defect Management

[iissmart]

I'm new to burning blu-rays (BD-RE specifically) so I've been reading a ton on disc formats, spare areas, fastwrite, etc.

What's not clear is whether ImgBurn's "Verify" functionality is equivalent (in terms of guaranteed burn accuracy) to the internal Hardware Defect Management functionality.

In other words, is it redundant to have spare areas enabled, fastwrite off, and Verify checked?

Since Hardware Defect Management slows the burn speed to 0.8x (for my discs), I'm considering using fastwrite to disable Hardware Defect Management (which makes spare areas pointless so I'd reformat without them), allowing me to burn at 2x and then use ImgBurn's Verify feature to re-read the disc at 4-8x. This should be faster than using Hardware Defect Management, but I'd like to know whether the integrity of the burn is verified the same way with just the Verify feature and no Hardware Defect Management.

Second question: Are spare areas transparent to the application reading the data? I'm wondering if I burn an iso created from a bit-for-bit image of a different disc (could be BD or DVD or CD) if having spare areas enabled or disabled will change the data on the disc (e.g. a hash of the disc will be different from the "master" iso, or if ripping the burned disc would result in a different iso than the original). It sounds to me like this would not be the case but I'd like confirmation about this as well. Thanks!

Edited January 6, 2021 by iissmart

[LIGHTNING UK!]

As verify re-reads the image and compares it at bit level against what's read from the disc, it can actually be better at finding problems. For example, if there's an issue with data corruption when reading from the source drive (but no 'hard' error) or a memory issue (faulty ram), verify would give you a 'miscompare' error. Hardware Defect Management won't notice that kind of thing.

As you say, it's pointless formatting with spare areas and then turning on fast write. Just format without spare areas.

Only if I really wanted to make sure everything was ok would I use hardware defect management AND verify. I don't think I'd rely on hardware defect management alone (as in, verify being disabled), but I'd certainly rely on verify alone (as in, without HDM being active during the writing phase).

Yes, spare areas are transparent to software. The drive handles remapped blocks itself internally.