[GreenKeys] OT: USENET article involving DEC machines and atomic tests

[Jones, Douglas W]

On Nov 18, 2016, at 4:03 PM, Jeffrey D Angus wrote:

> On 11/18/2016 3:50 PM, Dave Horsfall wrote:
>> Does anyone remember it?  It does sound rather suss...
> The resultant EMP would have cleared all of the core memory.

No, if it was a , it might have burnt out all the transistors, but the printed circuit board with the core on it had no transistors on board.  Those were all on the two "sister" boards.

Furthermore, this was an underground test, and the rock between the blast and the truck shields significantly against EMP, as does the electronics cabinet and the truck itself.

If you look at the DEC PDP-8 models from 1965-1980, you find that the PDP-8/E, 8/F and 8/M were packaged with boards that were uniquely ideal to survive a sudden upward explosion.  They were seated vertically in a horizontal backplane sitting below the boards.  An upward blast that breaks the structure of the relay rack would be unlikely to break the boards in this orientation.  All the other models of PDP-8 had boards that were more vulnerable.

Also, those and later PDP-8 models had core planes that were bonded with an elastomeric adhesive to the fiberglass printed circuit board instead of hanging in "window frame" suspension used by 1960s era core planes.  The result is that the core itself was not fragile.

So, the story passes my truthyness test.  I can't attest to its actual truth, but it is not ruled out by what I know of those DEC machines.  (I don't think any of the PDP-11 machines would have survived as well).

		Doug Jones
		jones at cs.uiowa.edu