Scanner freakishness [was Re: Python list vs google group]

[William Ray Wing]

> On Jun 16, 2018, at 9:10 AM, Steven D'Aprano <steve+comp.lang.python at pearwood.info> wrote:
> 
> On Sat, 16 Jun 2018 11:54:15 +1000, Chris Angelico wrote:
> 
>> On Sat, Jun 16, 2018 at 11:00 AM, Jim Lee <jlee54 at gmail.com> wrote:
> 
>>> I once had a Mustek color scanner that came with a TWAIN driver.  If
>>> the room temperature was above 80 degrees F, it would scan in color -
>>> otherwise, only black & white.  I was *sure* it was a hardware problem,
>>> but then someone released a native Linux driver for the scanner.  When
>>> I moved the scanner to my Linux box, it worked fine regardless of
>>> temperature.
>>> 
>>> 
>> I would be mind-blown if I did not have the aforementioned too many
>> hours. Sadly, I am merely facepalming. Wow.
> 
> 

Let me add one more story (true) to the list.  Concerns an old IBM mainframe installed in a bank in New York City, that crashed rarely, and only night, never during the day.  They called IBM; repair man spent the night with it - no crash; same story the next night and the next.  Finally on the forth night he left around 10:00 PM to get something to eat and some coffee.  Came back to find the computer had crashed.  Spent the next night - no crash.  Left the next again for coffee, came back to find the computer down.  Obviously it was only crashing when he wasn't watching.  Next night he left, but only took the elevator down to the ground floor, didn’t go outside.  Computer crashed.  He rebooted, restarted the job stream, left the computer room for the same length of time, but didn’t leave the floor.  No crash.

To make a long story short, it was the motor-generator set that ran the elevators.  During the day, there was enough constant elevator traffic so that the MG set never shut down and even it it did, there was enough load elsewhere in the building to make the start-up transient a relatively small perturbation.  At night it would time out, shut down, and when he called for the elevator late at night, the start-up transient was too much for the computer’s power regulators.

Earlier crashes turned out to be coincident with janitorial staff working extra late after special events.

Bill


> 
> -- 
> Steven D'Aprano
> "Ever since I learned about confirmation bias, I've been seeing
> it everywhere." -- Jon Ronson
> 
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> https://mail.python.org/mailman/listinfo/python-list