The Diamond Back name was first introduced by Western States Imports (a distributor) in the 80's. They were later sold to Raleigh, who continues to own, spec and sell them today.
They have a good line of mountain bikes from entry level up to medium/decent level but no really high-end mountain bikes (which you aren't interested in anyway . . . so never mind).
Diamondback bikes have been made in Taiwan and China but I think they're all manufactured in China these days.
Is that the kind of information you were seeking?
Rick / OCRR