Shark Tank: The long, hot summer

It's the long, hot summer of 1969, and this computer operations pilot fish is managing the night shift in the spanking-new computer room at a paper forms manufacturer.

The 2,500-sq.-ft., air-conditioned time-sharing center on the 10th floor of this building houses a pair of General Electric 265 mainframes on one side of the big room, with a pair of Digital Equipment Corp. PDP-10s, each using a PDP-11 as a time-sharing front end, on the other.

There's also a plug-style telephone switchboard and 160 dial-in ports for users to call in from across the state -- all in all, a wonder of late-1960s technology.

At least for a while.

"We started having intermittent crashes on the PDP-10s -- about 100 a month on each machine," says fish. "We traced the power, we debugged the operating system, we poked and prodded everything that could be -- and the computers kept crashing."

Meanwhile, the older GE machines aren't having any problems. But three-quarters of the users are handled by the PDP-10s, and the crashes are coming more often.

Fish reseats memory boards, checks ground connections and sends memory dumps to DEC, but no pattern emerges. Finally a DEC engineer arrives to track down the problem.

"Finding nothing inside the computer room or adjacent telecom room, the DEC engineer and I walked around the outside of the computer room looking for answers," says fish.

But there's not much to see. Besides the computer room, there's nothing on the 10th floor but pallets piled high with paper and carbon paper, waiting to be printed and assembled into forms.

At the recently installed freight elevator, fish and the engineer notice a bad odor coming from the shaft every time the doors open. "There was a swoosh that pushed out a rotten-egg smell," fish says.

But they don't hang around in the non-air-conditioned area. "Nothing here," says the engineer. "Let's get out of this heat and humidity."

Next morning, the engineer is checking circuit boards on the PDP-10s and points out to fish that all the thousands of soldered connections -- which should be shiny and silver -- have turned black.

In fact, they keep checking the PDP-10 backplanes day after day, and the connections actually seem to be shrinking.

"Something was getting into our environment and eating these solder connections," fish says. "We thought, What could it possibly be? What could make a solder connection shrink?"

Days go by. The heat from management to fix the problem keeps increasing. But they can't figure it out.

Until one day when they take another walk around the 10th floor -- past the huge stacks of paper, past the bad-smelling elevator shaft.

And then it hits them. "The dark color on the solder was the byproduct of an acid reaction!" says fish.

"The shrinking connections were from acid eating them away. The source of the acid was sulfur from the elevator shaft combined with the high humidity -- it created drops of acid in the air in the storage area.

"The intake for the air conditioning was pulling air in from the storage area, mainlining acid drops directly under the raised floor," says fish. "And the electrical connections in the bay of the PDP-10 were little magnets attracting the acid drops."

And why weren't the GE computers affected? "They were in the other half of the room, where the air conditioning was pulling air from the outside of the building," fish says.

So the mystery is solved. The company reroutes the air conditioning intake, DEC replaces all the circuit boards, and the PDP-10s stop crashing.

But it's not until months later that fish learns why there was sulfur coming up that elevator shaft in the first place.

"Over the winter," he says, "the company had tried to dig a water well to avoid paying for expensive city water for their other operations. When they struck sulfur, they filled the hole with dirt and boarded it up.

"Then they built the new elevator above that hole -- and the sulfur came wafting up through the loose dirt.

"They finally blocked off that elevator shaft at the lobby level, and poured concrete to seal off the hole."

Copyright © 2003 IDG Communications, Inc.

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