Re: Weird USB errors on HD

[Alistair John Strachan <s0348365@sms.ed.ac.uk>]

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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