Once in a while I'm struggling with coordinate systems, so I end up googling for it and most of time I find the nice post made by Obi Griffith. Time to time I find other very interesting ressources. The subject is very well documented but some information are scattered over different posts and/or blogs. This time I took the time to read and collect the information and tried to synthetise in one place (a GitHub repo). I know, it is an umpteenth place that will talk about the subject... but at least it is useful to me. Hoping it might be useful to others too.
Here is the address: https://juke34.github.io/coordinate_systems/
I find Pierre's comment on that post really insightful: Cheat Sheet For One-Based Vs Zero-Based Coordinate Systems
In other words, you'll never have to consider BAM's coordinate system unless you're writing a BAM parser.