Y2K and immortal executables

The problem, as I understand it, is that there are a lot of embedded computers which do date-related calculations that you'd never think of. An example was given on one of the Usenet news groups of an embedded system which controlled the outflow valve of a sewer pipe. It apparently operated by calculating high tide times based on an internal clock/ calendar. It failed Y2K testing. Now think of the results, had this happened "live". Raw sewage dumped at (potentially) low tide. A mess, if not a health hazard. More on-topic is the so-called "Time Dilation Effect" or "Echelin-Crouse Effect" which has been documented on older (and some not-so-old) PCs. Basically, it shows itself as a clock which seemingly jumps ahead on some post-1/1/2000 reboots. Over a few weeks, the clock appears to gain several months of time. In some cases, the system may then stop booting or lose track of ports until the clock is set back to before 1/1/2000. The root cause has been traced to unbuffered real-time clock chips. On a system with such a chip, the BIOS may attempt to read some data during a time when it is being updated and during which a flag value is present, instead of a real date. It only seems to occur post-1/1/2000 because the longer code path taken to calculate the Y2K date may take longer than the grace period the clock chip provides prior to an update. Messy stuff... <<<John>>>