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Will your new MacBook crash to the ground without MagSafe? (Yes.)

Will your new MacBook crash to the ground without MagSafe? (Yes.)

Will your new MacBook crash to the ground without MagSafe? (Yes.)
November 14
08:18 2015


Will your new MacBook crash to the ground without MagSafe? (Yes.)

The new 12-inch MacBook doesn’t come with a MagSafe magnetic power connector, prompting some to speculate that Apple is giving up on this handy safety feature. Should we be worried about our laptops hitting the floor when we trip over the cable?

Perhaps we should have read it as an omen that the MagSafe 2 adapter for older, original MagSafe connectors was listed as discontinued on the Apple Store in the US and Canada last week. It’s back in stock this week, but MagSafe’s future in new Mac laptops is uncertain with the revelation of the single-port MacBook. With just a USB-C connection for power, data, and display, MagSafe may be on its way to sing with the choir invisible.

That’s a shame because Apple has retrained people of all ages, and perhaps some animals, to not worry about Mac laptop power cables. Go ahead! Stand on it, trip over it, yank it–the force of the smallest effort pulls it free.

To quote Apple’s MagSafe patent:

…the surface area of two magnetically attracted halves determines the number of magnetic flux lines and therefore the holding force between them because the holding force is proportional to the contact area between the two magnetically attracted halves…

What they said.

A USB Type C (or USB-C) cable has no such advantage. It has two distinct differences: first, a USB-C male end, such as the tip of a cable, is plugged into a port, very much like larger and deeper Type A and Type B USB connections.

Second, while MagSafe was optimised to help with “non-axial” force – any direction except straight out – the USB-C style plug and jack suffer the worst from that. As astrophysicist Katie Mack said, “The genius of the MagSafe connector is that if you apply a force in any other direction it breaks the magnetic seal very easily, and then there’s virtually no force required to remove the connector entirely.”

New 12-inch MacBook: Will your new MacBook crash to the ground without MagSafe?New 12-inch MacBook: Will your new MacBook crash to the ground without MagSafe?New 12-inch MacBook: Will your new MacBook crash to the ground without MagSafe?New 12-inch MacBook: Will your new MacBook crash to the ground without MagSafe?New 12-inch MacBook: Will your new MacBook crash to the ground without MagSafe?New 12-inch MacBook: Will your new MacBook crash to the ground without MagSafe?

The new MacBook’s logic board doesn’t extend to the edges of the case, so if the USB-C port sustains damage, the rest of your MacBook could be unaffected. Assuming it hasn’t crashed to the floor.

Koenig says the port’s design doesn’t expose any portion of the sheet metal beyond the aluminum case. With enough oblique force, the cable’s metal head will be pinioned against the MacBook’s frame, not putting stress directly on the port. If the laptop is loose on a surface, pulling obliquely on the cable will almost certainly bring the laptop with it more reliably than in our “perfectly straight-out” thought experiment.

However, if the laptop is secured in some fashion–even if you’re holding it tightly in your hands–the cable’s male plug end is probably the weak point, and it would be torn off, said Koenig, leaving its shell in the USB-C port, potentially without causing any harm to the MacBook. The metal shell could then be removed carefully.

Trip the lightweight fantastic

At some level, I’m trying to reverse engineer Apple’s thinking around design and testing, both in its larger engineering participation in shaping USB-C, and in its particular implementation. All the calculations and exercises above have certainly been performed a thousand times in simulation and prototyping internally, shaping the development of the socket, logic board, external cables, and more.

In the end, it’s not really enough. Mac laptops are going to go crashing to the ground in vastly greater quantities than they have over the last several years. I’ve heard it said since Monday morning that MagSafe was the single best hardware feature Apple invented for its laptops, and I’m hard pressed to deny that–although extra-long battery life is nice, too.

Clearly, MagSafe was better and experts agree. I recommend retraining your toddlers now.

(Thanks also to Ramez Naam for schooling me in some of the physics and spitballing ideas.)

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SungSun

SungSun

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