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When Unix Clocks Hit 10-Digits Will Anything Break?
dannycarroll asks: "I've not heard this mentioned yet so I'll bite.
This weekend (depend on where you live) the Unix system clock hits 1.000.000.000 seconds since the Unix Epoch.
I heard about one or two applications that are vulnerable to a date overflow but I am wondering how many more are out there, unknown.
It's not the Y2k bug and consequences are far from it, but it seems to me that there has been too little attention paid to this potential problem.
As an example, I wonder how many Perl scripts out there use 9 digits for the date-stamp field instead of a delimiter?" I've been hearing about this from several different directions and it took me by surprise. I would think that most programs out there are using time_t or at least 32-bit integers by now if they are storing seconds-since-the-epoch (you would think we actually had learned something from the Y2K chaos). Are there any well known programs that might break because of this?
This article on KDE Dot News describes the the 1,000,000,000th second bug in KMail < 1.0.29.1. The problem stems from the index file format used (the time stamp is a 9-char fixed-width field). The index files (and therefore the mail folders) become corrupted when the time value is >= 10^9. This doesn't have anything to do with time_t, which on 32-bit systems is slated to roll over sometime in 2038. Systems with 64-bit timestamps (like pre-X Mac OS and VMS) won't roll over for the next 20,000 years.
In Soviet Russia, Jesus asks: "What Would You Do?"
I doubt there's a lot of software that explicitely depends on the date being nine digits. It's not like the Y2K bug, where the most convenient form to manipulate the date was often as a string. People using the Unix time for their date would normally find it easier to manipulate the value as an integer. As long as they stick to that they're fine.
Where there might be problems (and I'm guilty of doing this) is where the developer took advantage of the fact that dates sorted alphabetically also happen to be sorted temperally. Say you save dated information in files and incorperate the timestamp in the file name. When you read the file name back in it's a string. If you need the most recent data, it's tempting to sort it as a string and pick off the last item (especially if you're using Perl which makes this sort of manipulation really easy). Unfortunately string comparisons will stop working on Saturday ("1000000000" 999999999).
It is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail. - Abraham Maslow
Sun has released a technical bulletin on this. It doesn't appear to be NDA or confidental, but then again, they don't always label their stuff. (I had a problem with that once. Not even a copyright notice. They screamed and yelled when the document hit the net.)
l
They do, however, reference the following URL at the end of the bulletin --
http://www.mitre.org/research/y2k/docs/TIME_T.htm