The UNIX O/S has a solid & secure design to last 5 decades, as it celebrates it’s 50th anniversary on JAN 1st 2020 🙂 An interesting discussion follows on Y2K38 design limitation that is a long 18 years away & will be addressed in future

https://www.networkworld.com/article/3511428/unix-is-turning-50-what-does-that-mean.html

Unix time, also known as ‘epoch time,’ is the number of seconds that have passed since Jan 1, 1970. As Unix turns 50, let’s take a look at what worries kernel developers.   Unix (including Linux) systems store date/time values as the number of seconds that have elapsed since 1970-01-01 00:00:00 UTC in 32 bits. Unix systems won’t run into a Y2K type of problem until 2038 when dates stored as described above will overrun their 32-bit space allotments. But that’s 18 years from now, and kernel developers are already working on how they will avert disaster. It’s a bit too early to start panicking.

The year 2038 problem is sometimes referred to as the Y2K38 problem. We have until Tuesday, January 19, 2038 to address it. If the problem isn’t resolved, systems after that date may think it’s 1901. One way to address the problem would be to switch to 64-bit representations of date/time information. And, in the meantime, maybe after singing “Auld Lang Syne” this New Year’s Eve, you can sing “Happy Birthday” to Unix. It’s turning 50, and that’s still a very big deal.