Comment 80 for bug 228624

Hello Andrew :-)

Interesting analysis.

You are correct to write "The OP's report does not have the 'attempt to access beyond end of device' error message". That message was not reported here until https://bugs.launchpad.net/ubuntu/+source/linux/+bug/228624/comments/14 . I have seen a bewildering variety of error messages since 23 Nov 08!

By 7 March 09 intermittent read failures (despite the /etc/hal/fdi/policy/preferences.fdi workaround) had become so frequent I returned the drive under warranty and fitted a new drive pending replacement of the first. I backed out the /etc/hal/fdi/policy/preferences.fdi workaround and all was well for a week or so.

Then read failures began again. Now with a new replacement for the original drive I am often able to workaround the problem by moving the media to the other drive; if that doesn't work, cleaning the media often works; if that doesn't work, new media works (I am backing up to DVD so the read failures happen during verification and re-writing backup files to DVD is easy). In the early days of this problem, rebooting often got around the problem but that is less convenient now because of some long-running tasks.

I believe there is more than one bug here because so many different error messages and workarounds have been given in this report. The triggering cause may be deficient error recovery. The picture may be complicated by interactions amongst ubuntu components.

I will modify the backup script to log messages from /var/log/kern.log after a DVD read failure in the hope of building a statistical picture

Best

Charles