About once a year, the computer operating systems of a 24/7 warehouse for jet engine parts have to be updated.  That requires the whole warehouse to be shutdown for a few hours on third shift.

I came to work just before Saturday midnight for the upgrade.  The last of the second shift workers were leaving and turning off the lights.

It took an hour to run the shutdown procedure that put all the automatic equipment into safe mode and bring down the dozen PDP-11 machine control computers.

When all the equipment in the warehouse was finally dormant, I triggered the main VAX Cluster upgrade file.

It would take a couple of hours to run.  So, after checking the progress several times, I walked out of the computer room into the vacant shop.

In normal operation: the AGVs would creep around the floor beeping their Sono-Alerts; the trams would rumble overhead carrying parts in totes; the lifts would signal as they shuttled up and down from the AGV stations to the tram stops; and the incessant synthetic voices for ‘QC check required at workstation G24’ would echo around the shop.

But after shutdown it was eerily quiet.  Not a sound except for the muffled hum of the VAX cooling fans.

I took a stroll in the dark.  The only lights on were the EXIT signs over the doors.  I walked past the AGVs snuggled into their charging stations.  The picking cranes were tucked into their maintenance posts.  The work-in-process carousels were waiting at their lifts.  The QC announcements were temporarily dumb.  The ambient noise, normally making it difficult to hear conversations, was absent.


The upgrade finish around 04:30.  I ran a list of health checks for all the systems, then triggered the warehouse start-up procedure.

At first, nothing seemed to happen.

I thought about the hundred workers that would start to arrive in an hour or two with no warehouse to run.  Sweat started dripping down my forehead.

I checked a few more things…. everything okay.  Then I remembered, the first thing it does is decide what needs to be scheduled for shipment.

Oh, first things first.  Give it time.

I walked back out into the shop, keeping an eye on the control console.

In a minute, an AGV woke up.  “Beep, beep, beep,” and I had to jump out of its way.

A carousel clocked to a bin and removed a part.

Off in the distance I heard a tram’s steel wheel chirp as it rounded a turn.

A picking crane retrieved a tray and brought it forward to the worker’s station.

The conveyors started to roll, totes bumping up into queues.

The overall sound level approached normal…. then started to die down again.

I rushed back into the computer room.  Checked status… no faults.

In a few minutes, the death quiet had returned.

I was almost frantic.  What have I missed?  Where’s the hangup?

I heard an entrance door open and close, then a bank of lights flickered on.

Their back… and their billion dollar warehouse is down.

The foreman stuck his head into the computer room.  “My, this is cool.”

I said, “Not cool!  Nothing is running.”


“It seemed to start, but slowed down ten minutes ago.”

The foreman walked over to a packing station.  “The instructions are displaying, the parts are here.  Didn’t they put everything away last night?”

“Could you pack that part and see what happens.”

“Well, if the union doesn’t see me.”

He followed the instructions, packed the part in a box with cushioning, applied the pre-printed shipping label, then set the completed package in a tote on the conveyor to an AGV station.

“Beep, beep, beep,” came from an isle away.

I breathed a sigh of relief.  “All it needs is a worker to do the work.”

We walked around the shop together flipping on the overheads.  Fifty stations were ready for the workers.  I smiled and chuckled, “Like a beast waiting in the tall grass for humans to come by.”


The first shift workers began to arrive and the noise level returned to normal.

I told the foreman, “I’m beat, going to bed, but call me if there’s a glitch.”

As I drove home a frisson hit me.  I know the software, every line of code, every machine, every process.  But there’s more lurking in this warehouse now… than the sum of its parts.


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Originated: 4/14/1985 09:21 AM    Revised: 8/30/2016 12:07 PM