… and I suspect today is going to be a busy day.

Back in the day, when I was working with mainframes, we would have to “stop” the mainframe at the end of daylight saving.

And wait an hour.

Why?

Transaction time-stamping is the reason.  The mainframe would happily stamp transactions will this:
02:00:00 Transaction 1
02:00:01 Transaction 2
02:00:02 Transaction 3

And once we get to 3am, and changed the time back to 2am, the mainframe would start overwriting the previous 02:00 transactions
02:00:00 Transaction 671
02:00:01 Transaction 672
02:00:02 Transaction 3

So we stopped the mainframe for an hour.

Nowadays, I expect that IBM mainframes would write transaction times in GMT UTC, which gets around the message overwriting issues.

Of course, Microsoft & Palm PDAs will have issues, and therefore I expect today will be a busy day.

But some years ago, I was on an elevator in Philadelphia, coming down.  I was to address a conference at a hotel. 

And on that elevator a man said
"I hear Billy Graham is staying in this hotel".

And another man looked in my direction and said
‘Yes, there he is.  He’s on this elevator with us."

And this man looked me up and down for about ten seconds, and he said
"My, what an anti-climax."

- Billy Graham speaking at TED, on the Technology, Faith and Suffering