Date: Mon, 13 Apr 2009 11:04:05 +0200 From: Erik Trulsson <ertr1013@student.uu.se> To: Tim Judd <tajudd@gmail.com> Cc: yuri@rawbw.com, freebsd-questions@freebsd.org Subject: Re: Why USB harddrive is so slow under FreeBSD? Message-ID: <20090413090405.GA33082@owl.midgard.homeip.net> In-Reply-To: <ade45ae90904122327l2c13b3b7nf5c4c37d8978bad3@mail.gmail.com> References: <49E246EC.50702@rawbw.com> <ade45ae90904122327l2c13b3b7nf5c4c37d8978bad3@mail.gmail.com>
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On Mon, Apr 13, 2009 at 12:27:27AM -0600, Tim Judd wrote: > On Sun, Apr 12, 2009 at 1:54 PM, Yuri <yuri@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 Not quite. uhci and ohci are both just different ways of accessing USB 1.0 and 1.1 controllers. uhci is used for controllers from Intel and Via, while ohci is used for just about all other controllers. USB 1.0 and USB 1.1 both support 1.5Mbit/sec (Low Speed) and 12Mbit/sec (Full Speed) > 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. A normal USB controller chip will provide one or more UHCI or OHCI (but never both) interfaces for handling Low and Full Speed devices and one EHCI interface for handling Hi-Speed (480Mbit/sec) devices. If you have several USB controllers in your computer you can indeed see both uhci and ohci devices as well as several ehci 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-unsubscribe@freebsd.org" -- <Insert your favourite quote here.> Erik Trulsson ertr1013@student.uu.se
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