The leap second is the rare and obscure practice of occasionally adding a second to the Coordinated Universal Time (UTC) system that most of us use to set our watches. It's necessary, but not exactly computer friendly. In 2012 it crashed websites such as Reddit and Yelp and snarled up airline departures in Australia, so you'd think most computer experts would really hate them. After all, we have perfectly accurate timekeeping systems, such as the one used by GPS, that don't futz with leap seconds.

But it turns out many computer folks are OK with the leap second, including Linux's creator, Linus Torvalds.

We're going to get another leap second at the end of June, and Torvalds doesn't anticipate any major glitches this time around. A lot of software has been patched since the 2012 disaster. "Last time it happened, people spent some effort making sure it was fine afterwards. Hopefully that all stuck," he says. "That said, the reason problems happen in this space is because it's obviously rare and special, and testing for it in one circumstance then might miss some other situation. So I'd certainly expect a few people to worry."

Torvalds went on to pontificate about whether the creators of the POSIX standard, used by Linux and Unix operating systems, made a tragic mistake defining a day as exactly 86,400 seconds while, apparently contradicting themselves by simultaneously forcing computers to use the leap-second friendly UTC. Here's his rationale for keeping computers from switching away from UTC. It's classic Torvalds: Technical, opinionated, and pretty damned funny.

Linus Torvalds: It would just cause other problems instead. Many worse problems. Things like just timezones are already a absolutely horrid mess, and everybody actually tracking the leap second would in many ways be much much worse.

The POSIX way of basically making leap seconds disappear except for when the actual leap second itself happens kind of minimizes the impact for most common timekeeping situations. Yes, it causes some problems for when the leap second comes around, and yes, people who actually need to care about long-term time differences end up having to know about leap seconds, but 99.9% of all software (and certainly 99.9% of all users) will never need or want to care.

So the POSIX approach puts the pain where it belongs, and hides it from the vast majority of cases that really don't care. I think it was the right decision.

>Wear silly hats, get a banner printed that says "Leap Second Doomsday Party", and get silly drunk

There's another issue too: future time. Lots of computers care as much about dates many years in the future as about current time, and leap seconds are added kind of willy nilly. So a computer that thinks about future time cannot take leap seconds into account, because they haven't been specified yet. So then it couldn't work with POSIX time at all, but have to work with human dates instead. That would just not work. The whole point of POSIX time is to be a useful way to track time. It would lose its value if you cannot translate "At 12 noon in 20 years" to POSIX time due to some unknown possible future leap second in between.

WIRED: Maybe I'm naive, but it seems like maybe we'd be better off if we'd just left UTC to the humans and allowed the machines to roam free in the land of atomic time?

Torvalds: Well, most of the time, even the machines don't actually care about

that land of atomic time. Most of the time they care about time because people care about time - because they are tracking your mortgage payments, for example. So you can't really separate the two.

So you'd have to teach people to not care about the correlation of time to the sun, or the correlation of dates to the seasons. That doesn't sound very realistic.

The people and computers who really care about "atomic" time tend to be astronomers. For the rest of us - both people and computers - we're probably better off taking the POSIX approach to it, and just say "who cares", with a few unlucky people worrying about bugs happening because of the perversities of timekeeping.

Really, to the rest of us, just take the leap second as an excuse to have a small nonsensical party for your closest friends.

Wear silly hats, get a banner printed that says "Leap Second Doomsday Party", and get silly drunk. You'll blink, and it's over, but at least you'll have the hangover next day to remind you of that glorious but fleeting extra second.

And that's exactly how relevant it should be to most people.