It's funny that they keep renaming it and everyone still calls it AS/400. I remember when they wanted people to call it iSeries but everyone just still used AS/400. I didn't even know about the others you posted and I still use the AS/400 occasionally.
It's still updated by IBM and runs on POWER. It's just called "i" now.
I believe the naming went something like AS/400->iSeries->System i->System i5->i