Re: Weird USB errors on HD

From: Alistair John Strachan (s0348365_at_sms.ed.ac.uk)
Date: 07/20/05

  • Next message: Lukasz Spaleniak: "kernel oops, fast ethernet bridge, 2.4.31" 
    To: karim@opersys.com
Date:	Wed, 20 Jul 2005 15:53:09 +0100

    On Tuesday 19 Jul 2005 17:47, Karim Yaghmour wrote:
    > I have a usb-attached HD that I use from time to time. When it's connected
    > to my desktop through a hub it works flawlessly. When connected to my Dell
    > D600 Laptop, however, it sometimes randomly exhibits a loud click (as if
    > the heads went berzerk) and the device goes unrecognized (i.e. the USB
    > layer drops the device and then redetects it again; meanwhile there is FS
    > corruption.)

    I've noticed my laptop is less able to output the required current for my
    portable HD than my desktop; either way it's probably not a good idea
    exceeding the USB specifications for current output @ 5V, so I'd recommend
    you use a powered hub or external PSU (if the HD supports one).

    Also a (slightly) nasty but functional trick is to have the power in when the
    HD initially spins up, then remove the power. Once the drive has spun up it
    seems to use a lot less power.

    You can get special USB cables that link two USB ports' 5Vs together in
    parallel, which seems to help supply the necessary current; after the HD has
    spun up you can remove the second "dummy" USB connector (my laptop only has
    two USB ports and I require the second port). 

    -- 
Cheers,
Alistair.
personal:   alistair()devzero!co!uk
university: s0348365()sms!ed!ac!uk
student:    CS/CSim Undergraduate
contact:    1F2 55 South Clerk Street,
            Edinburgh. EH8 9PP.
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