[Gllug] Backup drive for CentOS 5 remote setup

[Andrew Farnsworth]

On Tue, Aug 17, 2010 at 9:41 AM, Frank Scott <lists at frasco.org.uk> wrote:

> On Tue, Aug 17, 2010 at 08:50:24AM -0400, Andrew Farnsworth wrote:
> > Power to the USB drive is limited by the USB standard to 500 mw or 1/2 a
> > watt.  If you are using a short chunky cable as opposed to a long thin
> one,
> > I would suspect the long thin one doesn't actually have the power wires
> and
> > is really just a 2 wire cable... not really a USB cable at all.  You
> could
> > check this with a multimeter pretty easily or try the same cable with
> > another USB powered device that uses less power.
> >
> > If you are running the drive off a server, you should not have to worry
> > about USB power as each port should supply up to 500 mw.  if you are
> > connecting these devices to a laptop that is not plugged in... then I
> would
> > worry.  Or if you were plugging them into an unpowered USB hub.  A
> powered
> > USB hub should supply 500 mw to each port... well the good ones anyway.
> >
>
> s/500 mw/500 mA/ or more strictly a high powered USB2.0 device can draw up
> to 5
> 100mA load units at 5.0+/- 0.25 V.
>

Frank,
  You are correct, I said mw and meant mA... at a nominal 5V that is 2.5
watts of power.

Andy
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.lug.org.uk/pipermail/gllug/attachments/20100817/8018dfff/attachment.html>
-------------- next part --------------
-- 
Gllug mailing list  -  Gllug at gllug.org.uk
http://lists.gllug.org.uk/mailman/listinfo/gllug