[plug] 2.5 USB Enclosure

Craig Ringer craig at postnewspapers.com.au
Sat Aug 6 01:31:24 WST 2005


On Fri, 2005-08-05 at 21:32 +0800, Chris Caston wrote:

> OK I had trouble with 10gb drives but not with 40gb and above.

It's entirely possible that the issues you encountered were to do with
power draw. Did you check the power requirements of the drives? IIRC USB
guarantees 500 milliamps (certainly < 1 amp) at 5V. Some host controller
implementations provide a *LOT* more than that when required, some stick
close to the standard. Laptops seem to be stricter about max power draw,
especially Intel-chipset laptops.

I've also found that all other things being equal, newer hardware tends
to be willing to supply more power. In particular, lots of manufacturers
seem to support much greater draws in USB2 chipsets, even though the
standard didn't increase the max permitted power draw for USB2 (AFAIK).

--
Craig Ringer




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