The strangest place I ever coded, was sitting in the bottom of an air-conditioned, rack-mount cabinet located in the warehouse section of a retail store in East London. I had to wear two each of jeans, socks, jumpers and the heaviest overcoat I could find. Also a pair of wooly gloves with the fingertips cut-off (generously provided by the store manager), to keep from freezing to death.
I was attempting to trace a spurious bug to do with RS232 communications between a AT-class pc and a hand-held terminal cradle. We had installed a data sniffer in the cabinet and had succeeded in capturing the event, but no amount of analysis could reveal the cause. In a final act of desperation, I had moved all the racks in the cabinet up to the top in order to free enough space at the bottom that I could sit inside with the door closed. Dust contamination was more of a concern that heat, but with the door closed the 8 AT-class machines in the cab generated enough heat for the airco to be necessary. I sat there for 4 1/2 hours (starting a 5 am, as that's when most occurances seem to happen) monitoring the data sniffer before I actually saw the glitch occur on the data sniffer.
What caused it? I couldn't tell. None of the other monitoring or tracing I had set up showed anything. At the point where the glitch occured, the warehouse was essentially deserted. Which ruled out one suspicion, that the electric forktruck used to offload trucks was somehow responsible.
Another thing that had been suspected was that as the CB radio craze has recently hit the UK along with batches of illegally high-powered sets from the far east. We had thought that maybe one of the regular delivery trucks had such a set and despite using double coaxial-shielded twisted pairs for the connection, that radio-frequency interference might be the source of the problem, but there where no trucks in the warehouse when it happened! The last one had left a few minutes before.
To cut an even longer story long, the problem turned out to be caused by the dry goods store next door. The other side of the wall against which the rack-cab was mounted turned out to be a frieght-lift. And the reason the problem only occurred in the am, was that is when they took delivery of their nuts. That is to say, once or twice a month, but always on a Monday, they had a delivery of peanuts, cashews, almonds, pestacho's etc. The problem was that because these goods are so heavy, it was possible to overload the lift which in turn caused arcing in the lift motors when they started. The associated radio frequency IR simply swamped the RS232 lines for a period of several seconds which in turn defeated all attempts in the communications protocol to detect and recover such anomolies.
I'll tell you, after four hours sitting on top of a pile of newspapers and some scrap of bubble wrap, hunched over a data sniffer, a 13 inch B&W monitor and a keyboard it was a long time before I complained about office chairs again.
In reply to Re: Strange Coding Tales
by BrowserUk
in thread Strange Coding Tales
by mojotoad
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