Sunday, November 8, 2009

taking turns literally through the roll of a dice

In my working and home life, I attempt to influence and control the outcome of many situations, either through direct intervention, quiet and not so quiet coersion, or subtle guestures that waft the course of affairs in the direction that I think is best. It works most of the time and the 80-20 rule sits well with me. But there are some things that refuse such influence.

One of these is the path to any one given destination. I experienced this today on my anniversary. We set off in the morning but rolled a dice to control our route. Evens go left, odds go right. This varied through the day to north-south, east-west, straight-right and left-straight. This seem to have the odd effect of having us follow the grey clouds and showers of rain, even down to the beach.

Not everything can be planned but you can have fun along the way by making the journey interesting. Hey, roll a six and you also get to change who is at the controls, after stopping safely of course.

Now I am wondering if this technique can also be used to determine which of the many high priority jobs I tackle at the start of each days work. The dice has 6 sides right. So by assigning a job to each number, this takes the hassle out of deciding which gets prime attention and should remove any guilt about not giving an equal amount of attention to the others. Now if only I could control the amount of unplanned work that the system itself generates then life would be easy.

Thursday, November 5, 2009

when a UPS on bypass is a bad idea

Under most normal circumstances, a UPS might seem like pretty good insurance for your vital computer systems. Pity we all work under conditions that make a war zone seem mundane.

So you have your UPS. Where do you think would be a good location for it. A clean air conditioned shack well away from any hazards. Not ours. For convenience it is located deep in a motor room basement where it is kept toasty warm by the excess heat from numerous rows of switching cabinets. But that's OK for when it rains, the overflow from the leaking gutters runs down the walls, splashes into the room containing the UPS and keeps it all cool.

So the UPS sits there quietly humming away, improving the quality of the feed voltage for delivery to the critical systems in the computer room. All is well until one day it overheats. No worries you say, it will simply switch to bypass. A little dirtier electricity but still good. The systems all stay active and the production line doesn't stop.

If only it were that simple. This week on the first scorching day prior to summer, the UPS overheated but instead of switching to bypass, it shut down completely. Seems it monitors the input voltage and only switches to bypass when this input voltage is within the "safe" levels preset in its config. Our input voltage fluctuates wildly due to the heavy loads imposed by 4 pretty big motors (1200V+10000A). It is usually well below the nominal 240V when production is active and can go 250V+ on weekends. On Tuesday, it was below the lower threshold so we ended up with an Unusable Power Supply not once but twice. Arrggghhhh.

Why do these things always seem to happen at the end of a day on my day off?