The new MacBook

Re:The new MacBook by mmastrac on Monday March 09, 2015 @01:50PM (#9172451)

Thunderbolt runs over USB-C, as well as DisplayPort. USB 3.1 features re-configurable lines that can negotiate almost any protocol. [1] [2]

[1] http://www.anandtech.com/show/8558/displayport-alternate-mod...

[2] http://www.anandtech.com/show/8539/usb-power-delivery-v20-an...

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Re:The new MacBook by djrogers on Monday March 09, 2015 @02:11PM (#9172615)

Displayport != Thunderbolt.

Displayport is a protocol that can run over a thunderbolt port, but the thunderbolt spec includes much more than that.

I don' believe we'll be seeing the 40Gbps PCI extension that is today's thunderbolt over USB 3.1.

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Re:The new MacBook by ajross on Monday March 09, 2015 @02:36PM (#9172830)

You're getting too tied up in brand identity and going too far in the other direction. What we call "Thunderbolt" is effectively an evolution of the DisplayPort PHY (which already supported graphics streaming of course, and also encapsulated USB transfers) with protocol extensions to do more PCI-like transactions.

And the USB 3.1 "SuperSpeed+" PHY is a 10Gbps thing that is very comparable to Thunderbolt electrically and would be expected to evolve similarly.

You're right that USB lacks the PCI framework (which many of us view as a feature). But DP/Thunderbolt similarly lacks a cabling standard with the sophistication of USB: no charging, not reversible connectors, no OTG-style switching of host/guest mode.

Apple had a choice of supporting both connectors, or giving up "PCI madness" or "nice cables" to get just one. They picked USB.

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Re:The new MacBook by mikeash on Monday March 09, 2015 @02:47PM (#9172944)

That's all well and good, but the question was whether it supported actual Thunderbolt, to which the answer given was "yes" but the actual answer appears to be "no."

Supporting something like Thunderbolt is nice, but not exactly the same. It's not about "brand identity," it's about "does this equipment I have work with this machine?"

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Re:The new MacBook by lsaferite on Monday March 09, 2015 @03:43PM (#9173438)

Just to clear up the FUD, the Type-C connector supports 'Alternate Modes.' This allows manufactures to implement chips that can MUX different signal types onto the USB cable SS lanes. There are 4 SS lanes that can be reassigned and either 2 or 5 additional wires that can also be used depending on if it's a cable or dock connection.

So, can the Type-C connector support Thunderbolt? Yes. Does the Type-C connector currently support Thunderbolt? No. Will someone add Thunderbolt over Type-C? Maybe.

I've only heard of PCIe over Type-C (via the spec docs) and DP over Type-C (from the VESA guys).

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Re:The new MacBook by mikeash on Monday March 09, 2015 @03:59PM (#9173563)

It certainly sounds like an excellent connector. If Apple can shoehorn Thunderbolt into that, it would be great. If they can't, it sounds like it's well worth it anyway.

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Re:The new MacBook by ajross on Monday March 09, 2015 @03:12PM (#9173190)

That's hardly unique to this situation though. It doesn't support Firewire or eSATA or VGA or ethernet or AppleTalk or Centronics parallel either. Life moves on, and this is hardly a company gripped by concerns for backwards compatibility.

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Re:The new MacBook by mikeash on Monday March 09, 2015 @03:22PM (#9173273)

You seem to have confused "Is this the end of Thunderbolt as well?" with "I hate Apple forever for changing things." It's a simple question with a simple answer. (Yes.)

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Re:The new MacBook by zoul on Monday March 09, 2015 @07:01PM (#9174686)

Life moves on, but Thunderbolt is such a new interface to be obsoleted.

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Re:The new MacBook by moe on Monday March 09, 2015 @02:53PM (#9173026)

They picked USB.

And thank goodness they did.

The "U" in USB may finally become reality. It's overdue.

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Re:The new MacBook by beagle3 on Monday March 09, 2015 @09:23PM (#9175382)

Does this mean that Thunderstrike (and previous PCI-based attacks) are not usable against the new Mac?

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Re:The new MacBook by ajross on Wednesday March 11, 2015 @02:53PM (#9186059)

No, there is no access to PCI address spaces over the USB 3 port. At least not yet, with existing hardware. As mentioned elsewhere in the thread it's not an impossibility to see an evolved (but compatible) standard in future USB 3 hardware.

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Re:The new MacBook by lsaferite on Monday March 09, 2015 @03:37PM (#9173391)

So, in alternate mode all 4 SS lanes can be reassigned. Each lane is doing 10Gbps right now from what the specs say. You could do PCIe over this and they even use PCIe as an example in the Type-C spec documents.

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Re:The new MacBook by afandian on Monday March 09, 2015 @01:58PM (#9172520)

I've not read those docs (sorry) but what if I want to run DisplayPort for my monitor and simultaneously plug in an external USB drive? Can a single line switch between protocols?

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Re:The new MacBook by mmastrac on Monday March 09, 2015 @02:00PM (#9172533)

Yes you can. IIRC you can run USB3.x-speed devices and one alt-mode over a single line.

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Re:The new MacBook by lsaferite on Monday March 09, 2015 @03:46PM (#9173471)

They will be able to MUX two DP lanes onto two of the USB SS lanes and keep one for USB 3.1 as well.

Also, there are dedicated wires for USB 2.0 as well that are separate from the SS lanes.

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Re:The new MacBook by lsaferite on Monday March 09, 2015 @04:06PM (#9173610)

Just to clarify what you said, Alternate Mode allows two directly connected devices to negotiate what the SS lanes and a few other wires are used for. The signaling that happens over the wires after negotiation is totally outside of the USB spec as the signals are simply MUXed onto the wires. In theory you could MUX anything over the wires as long as the signaling parameter fell within the specs defines for the cabling.

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Re:The new MacBook by chatmasta on Monday March 09, 2015 @02:06PM (#9172579)

I have two thunderbolt displays daisy chained into the single thunderbolt port on my 2013 MacBook Air. Each display is basically also a dock, with other peripheral ports in the back. It works very well because as I understand it thunderbolt is 10gbps transfer.

Does USB-C work the same way?

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Re:The new MacBook by toomuchtodo on Monday March 09, 2015 @02:13PM (#9172641)

This is exactly what I'm wondering. I only have one Thunderbolt display, but I want another, and am curious if I should hold out for a bit.

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Re:The new MacBook by chatmasta on Monday March 09, 2015 @02:43PM (#9172895)

I'm selling both mine as I will be traveling a lot in the next year. Email me at [email protected] if you want one. :)

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Re:The new MacBook by toomuchtodo on Monday March 09, 2015 @02:54PM (#9173036)

I'll do so! I travel frequently as well (100% remote worker), but I use Pelican cases to move all my kit around the world ;)

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Re:The new MacBook by lucaspiller on Monday March 09, 2015 @03:20PM (#9173246)

What cases do you have? I looked into these before, but anything with a decent size seemed too heavy to take on aircraft (assuming a 30kg checked in limit).

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Re:The new MacBook by toomuchtodo on Monday March 09, 2015 @03:39PM (#9173405)

I'll have to find the exact model numbers, but I don't bring it on aircraft, I ship it ahead of me.

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Re:The new MacBook by lsaferite on Monday March 09, 2015 @03:48PM (#9173480)

The DP over Type-C stuff (Alternate Mode) is not hub traversable.

So, you could talk to a single DP device, but that DP device could be a DP MST splitter. This could allow it to act as a DP hub for you to daisy chain a second monitor.

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