Apollo gave us the long term use of a DN1000.    I ported our image processing system to it.     The amusing thing was when you fired up an X window manager on the thing, it wrapped all three segments of the little status bar at the bottom with window borders.    The DN10000 docs came with a beautiful 5 volume set that described all the internals.   It was quite detailed for what was there.   What I really needed was the documentation on the graphics system which was in Volume 3.   My set was missing this.   After much digging around Apollo, it turns out that they never wrote volume 3, just assigned the volume number to some yet to be written document.

I learned the hard way not to open the gull wing doors on the thing while someone was using it.

When HP/Apollo merged and they formally pulled the plug on Domain, I was over at the FAA and they showed me the “latest” computer they got in that was running a system to show where all the planes in the airspace system were (think of FlightAware.COM, this was a first stab at pulling that data from the ATC computers).    It was a DN4000? running domain.   Always using the latest stuff at the FAA.