undefined | Better HN

0 pointsgmueckl1y ago0 comments

That reminded me of a former colleague at the desk next to me randomly exclaiming one day that he had just fixed a bug he had created 20 years ago.

The bug was actually quite funny in a way: it was in the code displaying the internal temperature of the electronics box of some industrial equipment. The string conversion was treating the temperature variable as an unsigned int when it was in fact signed. It took a brave field technician in Finland in winter, inspecting a unit in an unheated space to even discover this particular bug because the units' internal temperatures were usually about 20C above ambient.

0 comments

4 comments · 2 top-level

treyd1y ago· 2 in thread

This is a surprisingly common mistake with temperature readings. Especially when the system has a thermal safety power off that triggers if it's above some temperature, but then interprets -1 deg C as actually 255 deg C.

shakna1y ago

The rollout is still happening, but the new resident water meters for Victoria, Australia come with a temperature fix.

Prior to this year, they could only handle 0-127 degrees for the water temperature. Which used to be sensible, but there were some issues with pressurised water starting to be delivered to houses resulting in negative temperatures being reported, like -125C, which immediately has the water switch off to prevent icing problems.

The software side also switched from COBOL to Ada. So that's kewl.

selimthegrim1y ago

I have seen this on Walgreens signs in suburban New Orleans, oddly enough.

edarchis1y ago

My brother is a wifi expert at a hw manufacturer. He once had a case where the customer had issues setting the transmit power to like 100 times the legal limit. They happened to be an offshore drilling platform and had an exemption for the transmission power as their antenna was basically on a buoy on the ocean. He had to convince the developer to fix that very specific bug.

j / k navigate · click thread line to collapse