On Fri, 27 Nov 2009 tmhikaru@xxxxxxxxx wrote: > It is important to me to know exactly how the failure path operates. Please > explain to me what I will see happen. - Not knowing is driving me nuts. It goes like this. The computer sends a lot of READ commands to the drive. (For all we know the same thing might happen with WRITEs, but you didn't do any writing in the test data you sent.) Every now and then the drive fails to carry out a READ, for no apparent reason. Normally the computer then retries, and the READ succeeds the second time. But of course, success isn't guaranteed. When the retry does succeed, no error messages are printed in the log and everything continues normally. Occasionally the computer does not retry the READ -- in circumstances where it doesn't really need the data (optimistic readahead). When this happens, the failed READ does cause an error message to appear. The same thing would happen if the attempted retries were to fail. Whether or not this would result in lost or corrupted data, or remounted readonly filesystems, depends on the kind of data being read. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
