On Sun, Sep 02, 2007 at 10:14:58PM -0400, Alan Stern wrote: > > Please Cc me on any replies, since I'm not subscribe to this list. > > Thanks.
> It's quite possible there's a bug in the device, one that is somehow > triggered by Linux but not by Windows or Mac OS X. However I have no > idea what such a bug might be or how to avoid it. Well, my colleague found a solution: "The problem is that the Stealth MXP device can't handle transfers greater than 64 Kb at a time. By default, linux attempts to transfer 120Kb at a time resulting in corruption. The Windows default is 64Kb, so no corruption. My guess is that OS X is using 64Kb transfers as well. I changed the max_sectors value for my device (sdb at the moment) from 240 (240 sectors x 512 bytes per sector = 120Kb per transfer) to 128 (128 sectors x 512 bytes per sector = 64Kb per transfer) and was able to transfer a 3.2Gb file without error, unmount, remount, and verify there were no errors. When I set the max_sectors value to 136 (max_sectors must be in multiples of 8) reading the data showed errors. Setting it back to 128 and remounting allowed reading the data without errors. With the max_sectors value set to 128 fsck comes up clean. So there is the problem, but I don't know if this is a constraint of the chipset in the drive or a firmware fixable type thing. We will have to see what technical support at MXI has to say. The fix is simple. As root (change the device as needed)... echo 128 >/sys/block/sdb/device/max_sectors Changes to this value don't go into effect until the device is unmounted and remounted. Here is the page I found the solution on: http://www.linux-usb.org/FAQ.html#i5 " ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Linux-usb-users@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-users
