There's a mention of the Datamatic 1000 in Hugh Blair-Smith's "Left
Brains for the Right Stuff" (on the development of the Apollo Guidance
Computer software), and gives an account that the B&O D-1000 got
flooded when a rooftop water tank burst, and hot tubes met cold water.
Early work on the AGC was hosted on the D-1000 descendent, the
Honeywell 800 series (replacing an IBM 650). Blair-Smith describes
the H-800 as having eight execution contexts (sets of registers).