I don't know how many of you all remember late 1999.

[zonemaster]

7. Got news for you. That threat was real.

I worked at a tech company that had all kinds of software - both licensed (costing multiple millions of dollars, annually) and engineer-written. I know for a fact that some of that code definitely would have failed had we done nothing to handle the under-specified date format. In our group of a few hundred electrical engineers, all had tasks assigned to review code and look for date-format dependencies that might make the code misbehave after January 1st, 2000. Suspect code segments went into a long list for more detailed review and re-coding, where necessary. It took several weeks. It was real. Had we worked at a company that handled power grid, water treatment or other civil infrastructure, things would have been much more intense.

The fact that no major upsets happened is not a data point that the threat wasn't real. It is much more a testament to the dedication to 10's of thousands of engineers spending probably millions of man hours combing through code, setting up simulations and making fixes to an incredibly immense and critical codebase.