USB portable drive weirdness

[Colin McGregor]

--- Peter King <peter.king-H217xnMUJC0sA/PxXw9srA at public.gmane.org> wrote:
> I put a 2.5" drive in a portable enclosure, for
> backing up and transferring
> files, which connects to and draws power from a USB
> 2.0 cable. It works just
> fine on my laptop. Well, I plugged it into my
> desktop yesterday, and -- well,
> nothing. I mean nothing at all: no sign in dmesg
> that it even registered. It
> just wasn't there.
> 
> OK, I thought, somewhere along the line I probably
> haven't loaded the right
> USB modules, or USB_mass_storage, or whatever. Then
> I plugged in my USB flash
> drive. Came right up, recognized by dmesg, mounted
> just fine as a USB weapon
> of mass storage. So the USB subsystem seems to be
> working.
> 
> Tried the portable drive once more. Again, nothing.
> The drive light comes on
> so it *is* drawing power -- but no registration in
> dmesg. So I plugged it in
> my laptop, and there it is, no problem. Back on the
> desktop, nada.
> 
> What is going on here? Any ideas?

Max power draw on one USB port is 500 mA. Some 2.5"
drives with case can top that. My 2.5" drive case came
with a funny looking USB Y cable allowing it to plug
into 2 USB ports (i,e, it can draw 2 x 500 mA). My
first guess in all this is your in a marginal power
situation, the laptop can offer enough power, but the
desktop comes up slightly short...

Colin.

> -- 
> Peter King			 	peter.king-H217xnMUJC0sA/PxXw9srA at public.gmane.org
> Department of Philosophy
> 215 Huron Street
> The University of Toronto		    (416)-978-4951 ofc
> Toronto, ON  M5S 1A2
>        CANADA
> 
> http://individual.utoronto.ca/pking/
> 
>
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> GPG keyID 0x7587EC42 (2B14 A355 46BC 2A16 D0BC  36F5
> 1FE6 D32A 7587 EC42)
> gpg --keyserver pgp.mit.edu --recv-keys 7587EC42
> 

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