USB portable drive weirdness

[Lennart Sorensen]

On Wed, Aug 08, 2007 at 12:20:36PM -0400, Peter King wrote:
> Thanks for the quick responses. Here are the answers: (1) the portable drive
> enclosure does *not* have any connector for an independent power supply; and
> (2) it did indeed come with one of those funny Y-cables for two USB devices.
> Perhaps if I try a regular USB cable...? Hmm.
> 
> Suppose that the suggestion is right that my desktop is in a marginal power
> situation. (Strange but there you have it.) Are there any remedies, apart from
> giving up on the portable drive?

Make sure you use that Y cable and plug it into two seperate USB ports
on the host system (not into a hub).

Plug in the plug with the pass through first, then the regular one.
That way you get power first, then more power and usb data lines last.

I am not sure, but I think USB2 ports are supposed to handle more power
than USB1 ports.

Of course there is also the issue that a USB port is allowed to restrict
power to something like 50mA until a device registers and tells the
system what power it needs, after which the power may then provide more
pwoer and allow the device to go into full operation, or it may tell the
device that it can't provide that level of power and not start up the
device.  USB is funny that way.  So even with a second plug, some
systems may provide very little if any power on that second port since
there is no USB device there to request more power.

--
Len Sorensen
--
The Toronto Linux Users Group.      Meetings: http://gtalug.org/
TLUG requests: Linux topics, No HTML, wrap text below 80 columns
How to UNSUBSCRIBE: http://gtalug.org/wiki/Mailing_lists