Markus Kuhn
part 2

Hello again, and "What's in a date?"

Well we want to know when that next birthday arises or when that supper credit card we have expires. So, we mark it down on our calendar and it says...

02/03/99

Then we make a mental note not to forget February 3 1999 and we stick it into one of those electronic gadgets that helps us (a notebook, a palmtop or even a real computer of the 450MHZ kind!).

A few weeks later, your mom calls and asks about the date. You pull up the note and say "It is on the second of March next year."

You have just been the victim of the Y2K bug. He is sneaky and likes to showup in unexpected places. And he has made you mom very upset with you when February 4th rolls around and she missed the date!

However, if your mom is European and wrote the date down the same as you did, then she will get the date correct because the Europeans read the first two digits as the Month which is 02 for February. Magic!

OK, so we get the point about the month day thing, but what about the year?

Well lets look at your credit card's expiration date:

03/99

This is not a big problem since we know that there is not a month 99, at least on this continent, so the month must be March and the year must be 1999. So now we are a few years into the future.

03/02

Using good reason and logic, we say why yes it expires on March of 2002. We don't get into weather it is the first or last day of the month, this totally depends on the operator on duty when you try to make that last minute purchase because you got the wrong date in the first place.

But, there is that bug man again. This date is really suppose to be February of 2003. A big difference, especially if this is the date the computer uses to expire your insurance or drivers licensee for those who still use them.

Now, lets add a bit more complication to the picture.

02/03/04

What date is it?

Well if we decided to follow the ISO 8601 standard, then we at least would get the year correct. The standard states that the year occupies the first data field. Why get technical? Because the standard also says that this field should be 4 digits indicating the full year.

So we change the date to read:

2002/03/04

The year is OK. But the bugman will not give up. You have a fifty/fifty chance of getting the correct day and month.

the ISO group says, "Dates are to be YYYY-MM-DD." That is easy to say, but not easy to do. Remember all those PCs, and toaster, and coffee makers that only had two digits for the year. Well there are a host of databases and applications that have the same problem. And those clever programmers who, 50 years ago, decided that this bank will use a year of 00 as an indication of-

I think I will stop with the last one. there seems to be other bugs that cause this problem, but I don't seem to be able to convince the banks to change this feature.

The standard also allows you to enter dates as:

The 2-Digit Bandit really likes this. He has a 50-50 chance to catch those world travels at any time of day or night.

So today's question is: "Is it a computer problem or a people problem?"

My opinion is that it is a cultural problem. We tend to view the world through our own experiences. And, for that matter how else can we view the world around us.

Education is only as good as the programs around us.
And the programs around us,
Are only as good as the education around the programming paradyms.