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Comment by atoav | Hacker News Reader

One rule of programming I figured out pretty quick is: if there are two ways of doing it and there is a 50/50 chance of one being correct and the other one isn't, chances are you will get it wrong the first time.

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The USB rule.

First time is the wrong way up

Second time is also the wrong way up

Third time works

It's because of the quantum properties of USB connectors. They have spin 1/2.

I thought it was because USB connectors occupy 4 spatial dimensions.

That's good, because otherwise we'd never be able to find them when we need them.

Instead we always find a USB type mini B when needing a micro B, a micro B when needing a type C, and a type C when needing an extended micro B. If you reveal a spare extended micro B whilst rummaging around then it will in additional transpire that the next cable needed will be a mini B, irrespective of any prior expectation you may have held about the device in question.

A randomly occurring old-school full-size type B may be encountered during any cable search, approximately 1% of the time, usually at the same moment your printer jams.

What I really don't understand, however, is why I keep finding DB13W3s in my closet

Just 3, plus 1 imaginary.

It's like the Two General's Problem embedded in a single connector.

You never really know it's right until you take it out and test the friction against the other orientation.

I boosted my USB plugged-in-successfuly-on-first-try rate when I imagined the offset block in the cable male USB connector as being heavy, so it should be below the centerline when plugged into a laptop's female USB connector. (Only works when the connector is horizontal, but better than nothing.)

It's actually super easy and, atleast for me, was always intuitive. Most USB cables have their logo or something else engraved on the "top" with the air gap. And since the ports are mostly arranged the same way, there is rarely any problem. Maybe I am just too dumb to understand jokes, but it always confused me :(

People don't always have perfect sight, lighting etc to see it. Or know about that tip. Or remember what it signifies. Often you're fumbling, doing 2 things at once.

> lighting

This explain the Apple connector branding...

It's really only the sideways ones which give people trouble. Especially if it's sideways on the back of a computer (or tv) so you can't really see what you're doing).

Desktop computers are fairly easy too. The vast majority of towers have the motherboard on the right-hand side, so that can be treated as the "down" direction USB-wise.

I can't find a reference now. But from what I remember the logo is supposed to be on top facing the user when plugging a device in. This was part of the standard that defined the size/shape/etc of what USB is.

Intel added the satiric text about the rule with double-tongue depiction in one of their whitepapers around USB3 publication for a reason. Sadly couldn't find it.

Doesn't work with vertical slots.

I was ecstatic when I learned this piece of information a few years ago, and find it very useful when I'm able to use it. But I've come to learn that at least 50% of the time they either have no logo at all, or have something engraved on both sides in too small a size to be unambiguous. USB multiport hubs, mobile data cables, a lot of these little cables still need the 3 step process.

Even if marked correctly, it still doesn’t go in until you look at the socket.

USB-A connection is not a classic system, you have to collapse the wavefunction before the connectors can match.

The proper way is to always look first.

USB-C changed that to "It'll physically fit the first time, but good luck figuring out if it's going to work!"

Does it ever happen that USb-C works one way but not the other?

No, it's a reference to the fact that USB-C is really a meta-protocol, which can (and is) implemented in many different ways by manufacturers - and thanks to variation in power handling, it also carries the odd chance of frying your devices!

... Isn't progress wonderful?

(Jk, it's so much better than USB-A. But the wtf moments are real)

15 types of cables all called USB-C

I’m sure it’s an improvement.

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