The Year 2038 Problem

Early UNIX programmers had quite a sense of humor. In their documentation for the tunefs utility, a command-line program that fine-tuned the file system on the machine's hard disk, a note at the end reads "You can tune a file system, but you can't tune a fish." A later generation of UNIX authors, fearful that stuffy, humorless corporate drones would remove this cherished pun, added a programmer's comment inside the documentation's source code that read, "Take this out and a UNIX demon will dog your steps until the time_t's wrap around!"

On January 19, 2038, that is precisely what's going to happen.