I think it's from the '80's, a good quality mountain bike. I believe the Diamond Back/Diamondback thing is insignificant, as it was the same brand, just a change in the way they spelled it. I'm not terribly familiar with these (although I did own one once), so there could be more to it than that, I'm not positive. But again, the frame you describe and the components indicate a good quality bike (not top of the line, but not the low end, either) from the time period.
Diamond Back was used well into the early 1990s. The rights to the name was purchased in 1999 by Derby International, which was the company that owned Raleigh. The all chrome frame sounds mid-1980s. I suggest you check the date codes on some of the components.