I think Microsoft did it better back in 1993. They’re also using 64-bit numbers for datetime, but these numbers are integers, expressed in 100 nanoseconds ticks

I think Microsoft did it better back in 1993. They’re also using 64-bit numbers for datetime, but these numbers are integers, expressed in 100 nanoseconds ticks. That representation is used in NTFS, other components of Windows kernel and userland, .NET runtime including the modern Linux-running version, and quite a few other places. Y2038 is a non-problem, the representable range is about ±29000 years around the epoch. The extinction of the dinosaurs is not representable, but I think it’s OK in practice, only a small minority of software needs dates that far in the past or future. Accuracy is 2.5 times better than FP64, and is equal over the complete range.