[TUHS] Re: Sad news: Bell Labs leaving Murray Hill.

[jnc@mercury.lcs.mit.edu (Noel Chiappa)]

    > From: Ken Thompson

    > someone rewired someones desk lamp. i dont know how that worked out.

Sometimes electrical 'jokes' don't pan out - in a big way.

I was hacking the light switch in Jerry Saltzer's office (I don't recall
exactly what I was planning; IIRC, something mundane and lame like flipping
it upside down), and as I took it out of the box, the hot terminal touched
the side of the box (which was, properly, well grounded).

The entire 5th floor powered down.

What had happened was that the breaker for Jerry's office probably hadn't
been tripped in decades (maybe since it was put in), and it was apparently a
little sticky. Also, the floor had originally been wired back when all that
most people had in their offices, in the way of electrical load, was an
incandescent desk lamp or so. Now, most offices had, not just a couple of
terminals, most also had an Alto - greatly increased overall load. The total
draw for the whole floor was now very close to the rating of the main breaker
for the whole floor - and my slip of the hand had put it over. And that one
_wasn't_ sticky.

The worst part was that when we looked in the 5th floor electrical closet, we
couldn't find anything wrong. An electrician was summoned (luckily, or
unluckily, it was daytime; not having access to a 5th floor master, we'd gone
in while everything was unlocked - daytime), and he finally located the
breaker responsible - in an electrical closet on the 9th floor.

I got carpeted by Jerry, when he got back; I escaped without major
punishment,in part, IIRC, because I pointed out that I'd exposed a
previously-unsuspected issue. (I have this vague memory that the wiring on
the 5th floor was upgraded not long after.)


That wasn't the only historic CS building that has been abandoned. 545
Technology Square, one-time home of the Multics project, the MIT AI Lab,
and much else (including the above story) was exited by MIT some years
ago.

There, too, some history was abandoned - including the hack that allowed
people to call the elevators to their floor from their terminals. (Some
hackers had run some carefully disguised wires up into the elevator
controller - ran them along the back of structural members, carefully hidden
- and thence to the TV-11 that ran all the Knight TV bit-mapped displays
attached to the AI ITS time-sharing machine. So from a Knight TV console, if
you typed 'Escape E', it called the elevator to your floor - the code:

  https://github.com/PDP-10/its/blob/master/src/system/tv.147

even has a table - at ELETAB: - giving which floor each console was on, so it
got called to the correct floor. I wonder what happened to that when the
Knight TV system was ditched? Did it get moved to another machine? Actually,
I have a dim memory that the elevator people found it, and it was removed.)

	Noel