On Sun, Apr 12, 2009 at 1:54 PM, Yuri <y...@rawbw.com> wrote: > I have FreeBSD-71 running with USB controller: > uhci0: <VIA 83C572 USB controller> port 0xa800-0xa81f irq 21 at device 16.0 > on pci0 > > I connected to it Toshiba USB hard drive HDDR500E03X: > umass0: <Toshiba External USB HDD, class 0/0, rev 2.00/1.03, addr 2> on > uhub4 > da0: <Toshiba External USB HDD 1.03> Fixed Direct Access SCSI-4 device > > When I try to copy data with 'dd if=/dev/da0s1 of=/dev/null count=10000' it > only achieves has 0.65MB/s transfer speed. > > What's wrong, why is it so slow? > > Yuri >
uhci is 1.0 devices specs of 12Mbit/sec ohci is 1.1 devices ehci is 2.0 devices specs of 480Mbit/sec Seeing various PCs boot and during the probe, typically I see 1 ehci, and multiple uhci and ohci devices. Your Toshiba External USB HDD must have 2.0 speeds to be able to transfer at that speed... hooking a 2.0 device into a 1.x port will either cause port shutdown, or a backwards compatible downstep for the device in terms of speed. Hope this explanation helps. --TJ _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
