Peter Farrow wrote: > I tried a USB2 Maxtor One touch II external hard disk on > a couple of my Centos 4.2 boxes and found it initiallised > the SCSI subsystem ok and added device "sda". But the > performance is miserable, yet the same hardware running XP > the performance is satisfactory. What EHCI controller (brand/model)? I'd normally suggest you ensure you're connecting to an EHCI port with USBView (or Device Manager in Windows XP), but you've already stated that you had good performance in Windows XP. The only other thing I can suggest, which really isn't an answer, is to use FireWire. I've never had any performance issues, period. And there's no worrying whether or not you are connected to an OHCI or EHCI port, how well the driver handles memory mapped I/O for the target side, etc... FireWire was designed for block transfer devices, with intelligence allowing direct device-to-device transfers. USB was designed for character devices and programmed I/O, EHCI wasn't supposed to exist (but exists more out of Intel's refusal to license IEEE1394 -- long, long story -- which has affected adoption as well). -- Bryan J. Smith | Sent from Yahoo Mail mailto:b.j.smith at ieee.org | (please excuse any http://thebs413.blogspot.com/ | missing headers)