Re: [gentoo-amd64] Drivers For USB HDD

[Paul Hartman]

On Mon, May 7, 2012 at 4:18 PM, Michael Scherer
<a6702894@××××××××××××××.at> wrote:
>> On Mon, May 7, 2012 at 8:21 AM, Paul Hartman
>> <paul.hartman+gentoo@×××××.com> wrote:
>>>
>>> On Mon, May 7, 2012 at 10:00 AM, Mark Knecht <markknecht@×××××.com>
>>> wrote:
>>>>
>>>> here are 3 or now I
>>>> think 4 different USB specs - EHCI, OHCI, UHCI, and then whatever USB
>>>> 3.0 is using
>>>
>>>
>>> XHCI
>>>
>>> Furthermore, USB 3.0 has 9-pin ports and cables (for type-A) versus
>>> the 4-pin of USB 1/2. The USB 3.0 sockets are backward-compatible with
>>> older USB devices and cables, but older USB cables are not
>>> forward-compatible with USB 3.0.
>>>
>>
>> Good point. None of my USB 2.0 drives work in my USB 3.0 port. I do
>> have a USB 3.0 drivers, supposedly, and one drive that claims to be
>> eSata/USB 3.0 compatible, but I've not tried to get it working using
>> USB 3.0.
>>
>> - Mark
>>
>>
>

> Seems this either a typo, or a contradiction:
> "The USB 3.0 sockets are backward-compatible with older ... cables"
> would mean I can use the old cables for 3.0, but then
>
> "but older USB cables are not forward-compatible with USB 3.0"
> says I can NOT use the old cables.
> I have no 3.0, but some day I probably will, so I'd like to know what
> exactly you mean.
>
> kind regards
>
> michael

Hi,

Here is what I mean:

USB 3.0 socket is backwards compatible = USB 2.0 cable and devices
still work as USB 2.0 when plugged into USB 3.0 port.

USB 2.0 cable is not forward-compatible = you can not use USB 2.0
cable with USB 3.0 device as USB 3.0. It will only behave as USB 2.0
in that case.

If you want to truly use USB 3.0 you need to have all three: USB 3.0
port, USB 3.0 cable, USB 3.0 device.