Mac Musings

New DST Law to Impact Old Macs, Existing TV and VCRs, and More

Daniel Knight - 2005.08.10

Back in the American colonial period, Benjamin Franklin dreamt up Daylight Saving Time (DST) as a way to save money on candles and lamp oil. Whether he was serious about his proposal to move sunset back an hour or writing tongue-in-cheek is debatable (those who remember Franklin's "early to bed, early to rise" proverb tend to believe the latter).

Regardless, for most Americans - and much of the world - DST is here to stay.

DST was first imposed nationally in 1918 as a way to conserve resources during WWI, but that only lasted two years. DST was reinstated in 1942 and remainied in effect year-round until Sept. 30, 1945.

From 1945 through 1966, states were free to decide whether to adopt DST and when it would begin and end. That created a fair bit of confusion, and in 1966 the Uniform Time Act was passed, which set the last Sunday in April as the start of DST in the States and the last Sunday of October as the end.

The law has been modified twice since then. In 1986, the beginning of DST was moved to the first Sunday in April, and as of this week, beginning in 2007 DST will begin on the second Sunday in March and end on the first Sunday of November in the US.

For the record, the Department of Energy estimates that the US reduces its energy demands by about 1% each day that DST is in effect.

What's This Got to Do with Macs?

Early personal computers didn't track time when they were turned off. On early DOS PCs, you had to set the date and time manually each time you started the computer - otherwise your new files would have the wrong time stamp.

Needless to say, add-on date/time clocks became a popular accessory, and within a few years they were standard on all new PCs. That's been a standard feature of every Mac ever made, too.

In those days, you had to manually reset your computer's clock for DST, and over time a few DST control panels were released for the classic Mac OS. It wasn't until the OS 8.x era that Apple built automatic use of DST into the operating system.

Starting the second Sunday of March in 2007, that could cause all sorts of problems for Americans using Mac OS 8.x, 9.x, and early versions of OS X - and probably lots of people with Windows 95, 98, Me, etc. as well. The system clock will be off by an hour, and if it's changed manually, it will jump an additional hour on the first Sunday in April.

Once again, people with vintage operating systems will have to make a manual time adjustment - and then again on the last Sunday in October, when their computers will think DST has ended, and a fourth time on the first Sunday in November when DST really ends.

Expect Apple to address this in OS X 10.5 and later, and possibly 10.4.x as well, but don't expect them to release DST updates for earlier versions of OS X, let alone the classic Mac OS.

We anticipate freeware programmers will rise to the challenge and create system patches or Control Panels so low-end Macs and Windows PCs will be able to handle the new start and end dates transparently.

Don't Panic - or Do?

Computers aren't such a big deal. It's not difficult to reset the system clock.

But what about your VCR or television or PDA or digital watch - or any device that's hard wired to handle the DST transition on the first Sunday in April and the last Sunday in October?

If you're a geek, the words "firmware update" are jumping into your mind, but how in the world do you do a firmware update on a VCR, TV, or watch?

Right, you don't. You can't. (Even if you could, it wouldn't be cost-effective.) So you either put up with it for 4 weeks out of every year or buy a new TV and digital watch. (Your VCR will probably be obsolete by then, so that shouldn't be a worry. And you'll probably be able to download a patch for the better PDAs.)

Planning Ahead

What does that mean from now until the last Sunday in October 2006? Don't buy a TV, VCR, PDA, digital watch, or anything else that automatically handles the DST switch unless it can be updated for the change in 2007. (Some of these devices already let you specify the start and end of DST, which makes sense for any item with a worldwide market.)

Today might be a good day to see which electronic devices in your home may need to be updated or replaced before the third Sunday in March 2007.