Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1425341AbWLHKjh (ORCPT ); Fri, 8 Dec 2006 05:39:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1425342AbWLHKjh (ORCPT ); Fri, 8 Dec 2006 05:39:37 -0500 Received: from enyo.dsw2k3.info ([195.71.86.239]:57567 "EHLO enyo.dsw2k3.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1425341AbWLHKjg (ORCPT ); Fri, 8 Dec 2006 05:39:36 -0500 Message-ID: <457940DC.90403@citd.de> Date: Fri, 08 Dec 2006 11:39:24 +0100 From: Matthias Schniedermeyer User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.5) Gecko/20041217 Mnenhy/0.7 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Stefan Richter Cc: Robert Hancock , linux-kernel , DervishD Subject: Re: single bit errors on files stored on USB-HDDs via USB2/usb_storage References: <4578D97F.7020107@shaw.ca> <45792B4D.8050705@citd.de> <45793D82.1040807@s5r6.in-berlin.de> In-Reply-To: <45793D82.1040807@s5r6.in-berlin.de> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2176 Lines: 60 Stefan Richter wrote: > 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. It's a 5 port PCI-Addon-Card, no front panel connectors. (The computers has only an OHCI/USB 1.1 controller onboard, which i use for keyboard & mouse) >>>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. It'd guess that too, but who can that say for sure. :-| Bis denn -- Real Programmers consider "what you see is what you get" to be just as bad a concept in Text Editors as it is in women. No, the Real Programmer wants a "you asked for it, you got it" text editor -- complicated, cryptic, powerful, unforgiving, dangerous. - 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/