USB transfer speed

[Knut arne Vedaa]

When copying from a USB drive under Knoppix, I only get a transfer rate of about 1 MB/s. This would indicate USB 1.1 at 12 Mb/s. However, in USBView the port and the drive is identified as USB 2.0 (480 Mb/s). Is there any configuration that must be done is order for Knoppix to use the higher transfer rate?

[Paul Komski]

Which version of Knoppix?
http://www.knoppix.net/forum/viewtopic.php?t=15432

[Knut arne Vedaa]

It's version 3.8.1.

[Paul Komski]

Version 3.8.x should be at least kernel 2.6.x and thus have intrinsic USB support.

http://www.usbman.com/linuxusb.htm for A LOT of ideas

Notably: http://www.linux-usb.org/FAQ.html#gs6

Q: Does Linux talk to USB 2.0 devices?

A: Yes, in two ways. First the backward-compatible way: all high speed (480 Mbit/sec) devices can be used at full speed (12 Mbit/sec) in all current Linux kernels. Second if you have the EHCI driver, and a USB 2.0 host controller (EHCI, currently available as add-on PCI cards) then you can use these devices at high speed. EHCI support is available in the Linux 2.6 kernels, and also in 2.4.19 kernels. (The 2.4.19 code should handle USB disks nicely, but for more complete USB 2.0 support, use 2.6 instead.) At this writing the EHCI driver is labeled "experimental".


Are you sure all the hardware is USB2.0?

[Knut arne Vedaa]

Yes, it flies under Windows.

So does this mean that USB high speed should work out of the box on Knoppix >= 3.8? Can anyone confirm that it does? I've tried on two different machines, and copying 40 Gig to/from a USB disk took some 12 hours under Knoppix, and about 40 minutes under Windows... Which is rather unfortunate when you are using Knoppix to save files from a crashed Windows partition.

[Paul Komski]

USB2 support should be "native" in your distro. However not all hardware gets configured as one would want. Possibly manually mounting the drives might help (http://www.linuxquestions.org/questions/history/379483 relates to SuSE but might be worth reading)

http://www.linux-usb.org/usb2.html gives much more low-down on this subject and there may be other thoughts worth considering at http://forums.fedoraforum.org/showthread.php?t=84691

Could also possibly be worth grabbing the very latest version 4.0.x and/or using a cheat code to try to initialize the USB 2.x controller(s)
knoppix usb2 (from http://www.marcelgagne.com/cheatcodes.html) or press F2 at the start

Final though would be whether its actually a disk-caching issue. Can you copy large files across the main HDD without any speed problems.

[Knut arne Vedaa]

Thanks for your help.

Copying across the internal HD is fast. I've tried Knoppix 4.0.2, using "usb2" and "acpi=off", with both a USB HD and a USB memory stick - and the speed never exceeds 1 MB/s.

The USB controller identified as "USB Controller: Intel Corp. 82801EB/ER (ICH5/ICH5R) USB2 EHCI Controller (rev 02)".

Perhaps it just doesn't work. I might try some other live Linux CDs.

[Paul Komski]

My guess (and its only a guess) is that your problem relates to your hardware and not to Knoppix per se and for which the support should be present on the distros you have tried. Since you started this thread I have read around a lot and it does appear that some hardware can have such problems.

If would be interesting if you can get another live CD to work with high speed access.

Long shots would be to change any "Plug-n-Play" BIOS setting or a (not without risk) flash upgrade of the BIOS.