So it's no surprise that one morning he finds this message from someone on the help desk:
Seems that Branch X has dropped everyone's connection at 3:35 the last four days in a row. I checked the error log and see that a display adapter configuration error has popped up at the same exact second each day! Not sure how that works, but can one of you check on it to see what might be causing it? Faulty video card? Thanks!
A faulty video card doesn't sound likely to fish -- not if it's happening at exactly 3:35 p.m. every day.
But he knows some of the systems do share console monitors and keyboards through physical switches. And he knows that some of the servers automatically run a file cleanup task every morning, finishing up the process by rebooting.
Fish gets into Branch X's system via Telnet to check something. Then he sends a reply back to the help desk:
"Actually, the explanation is quite simple.
"Looking at the job schedule, we find that the 'daily purge' job runs at 3:31 every day, causing a reboot. Of course, this is meant to be 3:31 a.m. However, when I did a date command at 07:10 a few minutes ago, I got: Fri Jan 27 19:10:33 CST 2006.
"So the answer is, someone did a date command in the afternoon four days ago, resetting the date and time, and unfortunately forgot that you have to add 12 to the time when it's afternoon. The display error you're talking about occurs simply because the system is rebooted without any keyboard or display physically connected to the processor.
"I will go ahead and reset the time on Branch X's processor."