Messages in this thread | | | Date | Fri, 08 Dec 2006 11:25:06 +0100 | From | Stefan Richter <> | Subject | Re: single bit errors on files stored on USB-HDDs via USB2/usb_storage |
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Matthias Schniedermeyer wrote: > Robert Hancock wrote: >> Matthias Schniedermeyer wrote: >>> I have a 1,5 Meter and a 4,5 Meter cable connected to the USB-Controller >>> and i only use of them depending on where the HDD is placed in my room, >>> the other one is dangling unconnected. >>> >>> Then i will unconnect the short cable and use the long cable exclusivly >>> and see if it gets better(tm).
BTW, I suspect front panel connectors could introduce noise too, via the jumper cables from motherboard to the panel.
>> That long cable could be part of the problem - I don't think the USB >> specification allows for cables that long (something like a 6 foot max >> as I recall). > > http://en.wikipedia.org/wiki/USB2 > > Says that 5 meters are allowed.
I don't know about USB 2.0, but in case of FireWire, ~4.5m long cables are theoretically in spec too. I've got a FireWire 400 and a FireWire 800 cable this long, and both don't work very unreliable. Depending on what's connected, they fail sooner or later. However due to how FireWire works, this is immediately noticed as data CRC errors or bus resets. I.e. it's nearly impossible for noisy hardware to _silently_ cause data corruption. I would suppose USB has similar CRC checks.
Also, you mentioned that the corruption occurs systematically on certain byte patterns. Therefore it's certainly not related to the cables. -- Stefan Richter -=====-=-==- ==-- -=--- http://arcgraph.de/sr/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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