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M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

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Re: M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

#11

Post by fock »

nikanj wrote: post #6

USB went from being the universal bus, to just being the universal connector. There are never any guarantees that your device (or cable!) actually supports the operation you’re trying

I'm fine with devices offering different capabilities. But the cables should be marked clearly... I have one of the chinese drawing tablets, which has a convoluted "to USB-C" adapter. Apparently you can also drive it with USB-C directly, however only a manufacturer-provided cable (supershort) fits the port. Noone know what cable you can use alternately...

Re: M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

#12

Post by mccorrinall »

tjoff wrote: post #9
jon_adler wrote: post #4

Earlier quoted context omitted.

Bits to bytes means dividing by 8.

Just to add for clarity, b is used for bits and B for bytes. Though they are often mixed up. (... and a byte is not always 8 bits)

I believe the byte changed its meaning like many words did in the past. To a lot of younger developers a byte is synonymous with an octet.

Re: M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

#13

Post by smarx007 »

woodruffw wrote: post #5

The inability of the USB standards body to stick to a versioning scheme beggars belief: what in the world could "USB 3.1 Gen 2" possibly mean? Versions are free, why not simply name it "USB 3.2" and make the next one 3.3? "Gen 2" strikes me as the "Essay FINAL (final version 2).docx" of standards revisions.

I don't think it's an accident. I think manufacturers pressured the body to ensure they can always claim compatibility with the latest standard. For that purpose, version number became irrelevant and the profile name ("Gen 2") became important.

Re: M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

#14

Post by Hamuko »

woodruffw wrote: post #5

The inability of the USB standards body to stick to a versioning scheme beggars belief: what in the world could "USB 3.1 Gen 2" possibly mean? Versions are free, why not simply name it "USB 3.2" and make the next one 3.3? "Gen 2" strikes me as the "Essay FINAL (final version 2).docx" of standards revisions.

They're in an arms race with the HDMI Forum to make the most idiotic versioning scheme.

Re: M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

#15

Post by JadedBlueEyes »

mccorrinall wrote: post #12
tjoff wrote: post #9

Earlier quoted context omitted.

Just to add for clarity, b is used for bits and B for bytes. Though they are often mixed up. (... and a byte is not always 8 bits)

I believe the byte changed its meaning like many words did in the past. To a lot of younger developers a byte is synonymous with an octet.

In the CS tests for every UK exam board, a byte is always 8 bits

Re: M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

#16

Post by brigade »

LeoPanthera wrote: post #7
mlindner wrote: post #2

My initial suspicion would be the user used bad cables. There's many cables that say they're capable of a speed when they are not in fact capable.

If that was the case, the front non-thunderbolt ports would not be faster, but they are.

Getting USB 2.0 speeds strongly suggests that the cables somehow had horrendous signal integrity...

Anyway I grabbed a 3.1 gen2 SSD and plugged it directly into my 16" M1 Pro (Sandisk Extreme), and I got 850 MB/s read/write with his tool.

And that's supposedly one of the exact drives and laptops he tested. So something is going wrong for him, and it's 90% likely to be cables.

Re: M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

#17

Post by jon_adler »

mccorrinall wrote: post #12
tjoff wrote: post #9

Earlier quoted context omitted.

Just to add for clarity, b is used for bits and B for bytes. Though they are often mixed up. (... and a byte is not always 8 bits)

I believe the byte changed its meaning like many words did in the past. To a lot of younger developers a byte is synonymous with an octet.

A byte has been synonymous with an octet for as long as I can remember. I found a Wikipedia article [1] that describes the transition of a byte meaning the number of bits to encode character of text to an octet.

[1] https://en.wikipedia.org/wiki/Units_of_information

Re: M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

#19

Post by usrusr »

woodruffw wrote: post #5

The inability of the USB standards body to stick to a versioning scheme beggars belief: what in the world could "USB 3.1 Gen 2" possibly mean? Versions are free, why not simply name it "USB 3.2" and make the next one 3.3? "Gen 2" strikes me as the "Essay FINAL (final version 2).docx" of standards revisions.

But then you wouldn't be able to label-engineer your old chips into "the latest version" (of the old feature subset).

Isn't "USB 3.1 Gen 2" the usb 2 performance level as (re)specified in the USB 3.1 document set?

I'm deliberately writing without involving a search engine, to make my reply an authentic sample of the resulting confusion. My memory is probably wrong - and if it isn't, the lack of confidence still serves the purpose of illustrating the confusion.

Re: M1 Thunderbolt ports don’t fully support USB 3.1 Gen 2

#20

Post by WithinReason »

smarx007 wrote: post #13
woodruffw wrote: post #5

The inability of the USB standards body to stick to a versioning scheme beggars belief: what in the world could "USB 3.1 Gen 2" possibly mean? Versions are free, why not simply name it "USB 3.2" and make the next one 3.3? "Gen 2" strikes me as the "Essay FINAL (final version 2).docx" of standards revisions.

I don't think it's an accident. I think manufacturers pressured the body to ensure they can always claim compatibility with the latest standard. For that purpose, version number became irrelevant and the profile name ("Gen 2") became important.

Same thing happened with HDMI 2.1, all new features were defined as optional so everyone who only supports the 2.0 feature set can claim HDMI 2.1 compliance
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